timerfd: support CLOCK_BOOTTIME clock

Add CLOCK_BOOTTIME support to timerfd

Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 9293121..0013142 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -317,6 +317,7 @@
 	    (clockid != CLOCK_MONOTONIC &&
 	     clockid != CLOCK_REALTIME &&
 	     clockid != CLOCK_REALTIME_ALARM &&
+	     clockid != CLOCK_BOOTTIME &&
 	     clockid != CLOCK_BOOTTIME_ALARM))
 		return -EINVAL;