etc/kconfigs.yaml: add TEST_CLOCKSOURCE_WATCHDOG

This config was added by the following commit merged in v5.14-rc1

  commit 1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff
  Author: Paul E. McKenney <paulmck@kernel.org>
  Date:   Thu May 27 12:01:23 2021 -0700

      clocksource: Provide kernel module to test clocksource watchdog

Signed-off-by: Jiaqi Zhao <jiaqi.zhao@intel.com>

etc/kconfigs.yaml

@@ -249,6 +249,7 @@ TDX_GUEST_DRIVER: v6.2-rc1, x86_64
 TEST_BITMAP: v4.6-rc1
 TEST_BITOPS: v5.8-rc1
 TEST_BLACKHOLE_DEV: v5.3-rc1
+TEST_CLOCKSOURCE_WATCHDOG: v5.14-rc1
 TEST_DIV64: v5.13-rc1
 TEST_DYNAMIC_DEBUG: v6.1-rc1
 TEST_FPU: v5.9-rc1