tests: settings: enable ARM MPU

Remove CONFIG_ARM_MPU=n from all settings tests. This is possible due to
CONFIG_MPU_ALLOW_FLASH_WRITE=y automatically being enabled, which was not
true some time ago.

Enabling ARM MPU allows to detect stack overflows during tests runtime.

Signed-off-by: Marcin Niestroj <m.niestroj@emb.dev>

tests/subsys/settings/fcb/testcase.yaml

@@ -5,7 +5,6 @@ tests:
       - nrf52840dk_nrf52840
     tags: settings_fcb
     extra_configs:
-    - CONFIG_ARM_MPU=n
     - CONFIG_STDOUT_CONSOLE=y
   system.settings.fcb.raw_native_posix:
     platform_allow: native_posix native_posix_64

tests/subsys/settings/fcb_init/prj.conf

@@ -4,7 +4,6 @@ CONFIG_STDOUT_CONSOLE=y
 CONFIG_FLASH=y
 CONFIG_FLASH_PAGE_LAYOUT=y
 CONFIG_FLASH_MAP=y
-CONFIG_ARM_MPU=n
 CONFIG_FCB=y
 
 CONFIG_SETTINGS=y

tests/subsys/settings/file/testcase.yaml

@@ -7,7 +7,6 @@ tests:
     tags: settings_file settings_file_littlefs
     extra_configs:
     - CONFIG_STDOUT_CONSOLE=y
-    - CONFIG_ARM_MPU=n
   system.settings.file.raw_native_posix:
     platform_allow: native_posix native_posix_64
     tags: settings_file settings_file_littlefs

tests/subsys/settings/functional/fcb/prj.conf

@@ -4,7 +4,6 @@ CONFIG_STDOUT_CONSOLE=y
 CONFIG_FLASH=y
 CONFIG_FLASH_PAGE_LAYOUT=y
 CONFIG_FLASH_MAP=y
-CONFIG_ARM_MPU=n
 CONFIG_FCB=y
 
 CONFIG_SETTINGS=y

tests/subsys/settings/functional/file/prj.conf

@@ -1,5 +1,3 @@
-CONFIG_ARM_MPU=n
-
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_ZTEST_STACK_SIZE=2048