Revert "toolchain: gcc: Remove ref. to undefined sym. CONFIG_ISA_ARM"
Revert "toolchain: gcc: Remove ref. to undefined sym. CONFIG_ISA_ARM"

This reverts commit e20fd5f454b4b4e3ed7b94d88ac514c3f9928c04.

This is needed for Cortex-R support.

Signed-off-by: Bradley Bolen <a46f022a58b40f08f87b914d58da7dec46dba40c@lexmark.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,nashif/zephyr,finikorg/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr