[nrf fromtree] tests: llext: Set min_ram requirement for readonly_mpu…

… variant

Set the minimal RAM requirement for the test variant, so that it does
not get built for platforms it won't fit anyway.

Signed-off-by: Robert Lubos <[email protected]>
(cherry picked from commit 328ff9a)

tests/subsys/llext/hello_world/testcase.yaml

@@ -13,6 +13,7 @@ tests:
       - arch:arm:CONFIG_ARM_MPU=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=n
   llext.simple.readonly_mpu:
+    min_ram: 128
     arch_exclude: xtensa # for now
     filter: CONFIG_CPU_HAS_MPU
     extra_configs: