timerfd: support CLOCK_BOOTTIME clock

Add CLOCK_BOOTTIME support to timerfd
Signed-off-by: NGreg Hackmann <ghackmann@google.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

fs/timerfd.c

@@ -317,6 +317,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	    (clockid != CLOCK_MONOTONIC &&
 	     clockid != CLOCK_REALTIME &&
 	     clockid != CLOCK_REALTIME_ALARM &&
+	     clockid != CLOCK_BOOTTIME &&
 	     clockid != CLOCK_BOOTTIME_ALARM))
 		return -EINVAL;