boards/pyocd: cleanup use of export keyword

[aabadie]

Contribution description

Similar to #13480 and #13567, this PR removes uses of export for variables used by PyOCD.

Testing procedure

• Flashing/Resetting/Debugging the related boards should still work:

nrf52832-mdk

• flash

$ PROGRAMMER=pyocd make BOARD=nrf52832-mdk -C examples/hello-world --no-print-directory flash
Building application "hello-world" for "nrf52832-mdk" with MCU "nrf52".

"make" -C /work/riot/RIOT/boards/nrf52832-mdk
"make" -C /work/riot/RIOT/core
"make" -C /work/riot/RIOT/cpu/nrf52
"make" -C /work/riot/RIOT/cpu/cortexm_common
"make" -C /work/riot/RIOT/cpu/cortexm_common/periph
"make" -C /work/riot/RIOT/cpu/nrf52/periph
"make" -C /work/riot/RIOT/cpu/nrf5x_common
"make" -C /work/riot/RIOT/cpu/nrf5x_common/periph
"make" -C /work/riot/RIOT/drivers
"make" -C /work/riot/RIOT/drivers/periph_common
"make" -C /work/riot/RIOT/sys
"make" -C /work/riot/RIOT/sys/auto_init
"make" -C /work/riot/RIOT/sys/newlib_syscalls_default
"make" -C /work/riot/RIOT/sys/stdio_uart
   text	   data	    bss	    dec	    hex	filename
   8048	    108	   2552	  10708	   29d4	/work/riot/RIOT/examples/hello-world/bin/nrf52832-mdk/hello-world.elf
/work/riot/RIOT/dist/tools/pyocd/pyocd.sh flash /work/riot/RIOT/examples/hello-world/bin/nrf52832-mdk/hello-world.hex
### Flashing Target ###
[====================] 100%
0001838:INFO:loader:Erased 8192 bytes (2 sectors), programmed 8192 bytes (2 pages), skipped 0 bytes (0 pages) at 10.89 kB/s
Done flashing

• reset

$ PROGRAMMER=pyocd make BOARD=nrf52832-mdk -C examples/hello-world --no-print-directory reset
/work/riot/RIOT/dist/tools/pyocd/pyocd.sh reset
### Resetting Target ###
Resetting target

• debug

PROGRAMMER=pyocd make BOARD=nrf52832-mdk -C examples/hello-world --no-print-directory debug
/work/riot/RIOT/dist/tools/pyocd/pyocd.sh debug /work/riot/RIOT/examples/hello-world/bin/nrf52832-mdk/hello-world.elf
### Starting Debugging ###
Reading symbols from /work/riot/RIOT/examples/hello-world/bin/nrf52832-mdk/hello-world.elf...
0000231:INFO:board:Target type is nrf52
0000293:INFO:dap:DP IDR = 0x2ba01477 (v1 rev2)
0000347:INFO:ap:AP#0 IDR = 0x24770011 (AHB-AP var1 rev2)
0000356:INFO:ap:AP#1 IDR = 0x02880000 (proprietary)
0000358:INFO:target_nRF52:NRF52832 not in secure state
0000368:INFO:rom_table:AP#0 ROM table #0 @ 0xe00ff000 (designer=244 part=006)
0000377:INFO:rom_table:[0]<e000e000:SCS-M4 class=14 designer=43b part=00c>
0000383:INFO:rom_table:[1]<e0001000:DWT class=14 designer=43b part=002>
0000389:INFO:rom_table:[2]<e0002000:FPB class=14 designer=43b part=003>
0000395:INFO:rom_table:[3]<e0000000:ITM class=14 designer=43b part=001>
0000401:INFO:rom_table:[4]<e0040000:TPIU-M4 class=9 designer=43b part=9a1 devtype=11 archid=0000 devid=0:0:ca1>
0000407:INFO:rom_table:[5]<e0041000:ETM-M4 class=9 designer=43b part=925 devtype=13 archid=0000 devid=0:0:0>
0000410:INFO:cortex_m:CPU core #0 is Cortex-M4 r0p1
0000418:INFO:cortex_m:FPU present: FPv4-SP
0000423:INFO:dwt:4 hardware watchpoints
0000427:INFO:fpb:6 hardware breakpoints, 4 literal comparators
0000444:INFO:server:Semihost server started on port 4444
0000444:INFO:gdbserver:GDB server started on port 3333
Remote debugging using :3333
0001400:INFO:gdbserver:One client connected!
pm_set_lowest () at /work/riot/RIOT/cpu/cortexm_common/include/cpu.h:177
177	    irq_restore(state);
0001487:INFO:gdbserver:Attempting to load Argon
0001487:INFO:gdbserver:Attempting to load FreeRTOS
0001488:INFO:gdbserver:Attempting to load Zephyr
0001489:INFO:gdbserver:Attempting to load RTX5
(gdb) load
Loading section .text, size 0x1f70 lma 0x0
Loading section .relocate, size 0x6c lma 0x1f70
[====================] 100%
0005768:INFO:loader:Erased 0 bytes (0 sectors), programmed 0 bytes (0 pages), skipped 8192 bytes (2 pages) at 11.31 kB/s
Start address 0x420, load size 8156
Transfer rate: 11 KB/sec, 1359 bytes/write.
(gdb) l
172	    __WFI();
173	#if defined(CPU_MODEL_STM32L152RE)
174	    /* STM32L152RE crashes if branching to irq_restore(state). See #11830. */
175	    __set_PRIMASK(state);
176	#else
177	    irq_restore(state);
178	#endif
179	}
180	
181	/**
(gdb) quit
A debugging session is active.

	Inferior 1 [Remote target] will be detached.

Quit anyway? (y or n) EOF [assumed Y]
Detaching from program: /work/riot/RIOT/examples/hello-world/bin/nrf52832-mdk/hello-world.elf, Remote target
0013915:INFO:gdbserver:Client detached
0013916:INFO:gdbserver:Client disconnected!
Remote communication error.  Target disconnected.: Connection reset by peer.

• Plug multiple boards and try to flash one of them based on its DEBUG_ADAPTER_ID

Issues/PRs references

Related to #10850

[fjmolinas]

Nice cleanup, I do not have any of the boards ATM, maybe @bergzand can give it a test?

[bergzand]

I'm still able to flash a particle-xenon board with this PR

[fjmolinas]

@bergzand tested. Changes make sense ACK!