tests: arch: arm: arm_custom_interrupt: Excluding Renesas RA

Renesas RA ICU already selects ARM_CUSTOM_INTERRUPT_CONTROLLER,
so it will be excluded from the test.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

tests/arch/arm/arm_custom_interrupt/testcase.yaml

@@ -7,4 +7,5 @@ common:
   arch_allow: arm
 tests:
   arch.arm.custom_interrupt:
-    filter: not CONFIG_TRUSTED_EXECUTION_NONSECURE
+    filter: not CONFIG_TRUSTED_EXECUTION_NONSECURE and
+            not dt_compat_enabled("renesas,ra-interrupt-controller-unit")