tests: kernel: mem_protect: protection: fix test-case filter
tests: kernel: mem_protect: protection: fix test-case filter

The test is to run for boards that have memory protection
enabled; having MPU capabilities on the SoC level is not
sufficient (the user, or the board itself, might not enable
memory protection support). This commit applies that policy
to the mem_protect/protection test suite.

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

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