arch: increase priv stack with built-in stack-overflow checking
arch: increase priv stack with built-in stack-overflow checking

This commit increases the privilege stack size to 512 bytes,
when building with support for built-in stack-overflow checking.
This is in alignment with #10729, which increases the privilege
stack size when MPU-based stack guarding is enabled.

Signed-off-by: Ioannis Glaropoulos <5921cc8bab7e1d4329f52fd8f6268f9692e3de80@nordicsemi.no>

punitvara/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,nashif/zephyr,explora26/zephyr,finikorg/zephyr,Vudentz/zephyr,explora26/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,Vudentz/zephyr,galak/zephyr,galak/zephyr,nashif/zephyr,ldts/zephyr,punitvara/zephyr,Vudentz/zephyr,explora26/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,punitvara/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,nashif/zephyr,explora26/zephyr,explora26/zephyr,finikorg/zephyr,ldts/zephyr,nashif/zephyr,punitvara/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr