gcc-sanitizers: don't use thumb for armv[45]

* otherwise it fails with:
  sanitizer_linux.s:5749: Error: lo register required -- `ldr ip,[sp],yoctoproject#8'

@ 1538 "../../../../../../../../../work-shared/gcc-8.1.0-r0/gcc-8.1.0/libsanitizer/sanitizer_common/sanitizer_linux.cc" 1
        swi 0x0
cmp r0, #0
bne 1f
ldr r0, [sp, #4]
ldr ip, [sp], yoctoproject#8
blx ip
mov r7, #1
swi 0x0
1:
mov r0, r0

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gcc/gcc-sanitizers_8.1.bb

@@ -1,2 +1,7 @@
 require recipes-devtools/gcc/gcc-${PV}.inc
 require gcc-sanitizers.inc
+
+# Building with thumb enabled on armv4t armv5t fails with
+# sanitizer_linux.s:5749: Error: lo register required -- `ldr ip,[sp],#8'
+ARM_INSTRUCTION_SET_armv4 = "arm"
+ARM_INSTRUCTION_SET_armv5 = "arm"