[marvell-armhf][uboot-setting] Fix the print menu for marvell-armhf p…

…rint menu on Nokia-7215 (sonic-net#13933)

Why I did it
After sonic-install install a new image, print_menu is set echo without any data. No image info between Hit any key to stop autoboot:  0 and  Start USB

Board configuration detected:
Net:   
|  port  | Interface | PHY address  |
|--------|-----------|--------------|
No ethernet found.
Hit any key to stop autoboot:  0 

(Re)start USB...
USB0:   Port (usbActive) : 0    Interface (usbType = 2) : USB EHCI 1.00
scanning bus 0 for devices... 3 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
How I did it
The fw_setenv print_menu is missing the double quotes. That causes the value is truncated. Using double quotes to in the environment setting.

How to verify it
Install new image with this fix. And reboot the system. The following section should be shown:

Signed-off-by: mlok <marty.lok@nokia.com>

platform/marvell-armhf/platform.conf

@@ -175,7 +175,7 @@ prepare_boot_menu() {
         BOOT3='echo " > Boot3: ONIE - run onie_nand_boot";echo;'
     fi
     BORDER='echo "---------------------------------------------------";echo;'
-    fw_setenv ${FW_ARG} print_menu $BORDER $BOOT1 $BOOT2 $BOOT3 $BORDER > /dev/null
+    fw_setenv ${FW_ARG} print_menu "$BORDER $BOOT1 $BOOT2 $BOOT3 $BORDER" > /dev/null
 
     fw_setenv ${FW_ARG} linuxargs "net.ifnames=0 loopfstype=squashfs loop=$image_dir/$FILESYSTEM_SQUASHFS systemd.unified_cgroup_hierarchy=0 varlog_size=$VAR_LOG_SIZE loglevel=4 ${extra_cmdline_linux}" > /dev/null
     fw_setenv ${FW_ARG} linuxargs_old "net.ifnames=0 loopfstype=squashfs loop=$image_dir_old/$FILESYSTEM_SQUASHFS systemd.unified_cgroup_hierarchy=0 varlog_size=$VAR_LOG_SIZE loglevel=4" > /dev/null