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 <[e-mail]>
Cc: Prarit Bhargava <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Richard Cochran <[e-mail]>
Signed-off-by: John Stultz <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

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

···
 
 	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;
 	}