tests/kernel: timer_api: Enable Test userspace

timer_api requires TEST_USERSPACE activation which is missing
in tickless configuration of the test.
Enable flag in prj_tickless.cnf

Fixes #20904


Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

tests/kernel/timer/timer_api/prj_tickless.conf

@@ -3,3 +3,5 @@ CONFIG_SYS_POWER_MANAGEMENT=y
 CONFIG_TICKLESS_KERNEL=y
 CONFIG_MP_NUM_CPUS=1
 CONFIG_TEST_RANDOM_GENERATOR=y
+
+CONFIG_TEST_USERSPACE=y

tests/kernel/timer/timer_api/testcase.yaml

@@ -6,4 +6,4 @@ tests:
     build_only: true
     extra_args: CONF_FILE="prj_tickless.conf"
     arch_exclude: riscv32 nios2 posix
-    tags: kernel
+    tags: kernel userspace