arc: core: Fix possible overrun
arc: core: Fix possible overrun

dyn_reg_info has MPU_DYNAMIC_REGION_AREAS_NUM elements, just changing
the if check to be greater equal to this number to avoid access
MPU_DYNAMIC_REGION_AREAS_NUM element causing an out-of-bounds write.

CID: 205648
Fixes #20487

Signed-off-by: Flavio Ceolin <979b9165500b0741b9d0500e2efd74fc1547bff7@intel.com>

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