kselftests: timers: Make set-timer-lat fail more gracefully for !CAP_WAKE_ALARM

The set-timer-lat test fails when testing CLOCK_BOOTTIME_ALARM
or CLOCK_REALTIME_ALARM when the user isn't running as root or
with CAP_WAKE_ALARM.

So this patch improves the error checking so we report the
issue more clearly and continue rather then reporting a failure.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/timers/set-timer-lat.c

@@ -139,6 +139,13 @@ int do_timer(int clock_id, int flags)
 
 	err = timer_create(clock_id, &se, &tm1);
 	if (err) {
+		if ((clock_id == CLOCK_REALTIME_ALARM) ||
+		    (clock_id == CLOCK_BOOTTIME_ALARM)) {
+			printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
+					clockstring(clock_id),
+					flags ? "ABSTIME":"RELTIME");
+			return 0;
+		}
 		printf("%s - timer_create() failed\n", clockstring(clock_id));
 		return -1;
 	}