timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond

Commit 6b43ae8a61 (ntp: Fix leap-second hrtimer livelock) broke the
leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to
wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC.

Adjust wall_to_monotonic when NTP inserted a leapsecond.

Reported-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Richard Cochran <richardcochran@gmail.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1338400497-12420-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/timekeeping.c

@@ -962,6 +962,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
 		timekeeper.xtime.tv_sec++;
 		leap = second_overflow(timekeeper.xtime.tv_sec);
 		timekeeper.xtime.tv_sec += leap;
+		timekeeper.wall_to_monotonic.tv_sec -= leap;
 	}
 
 	/* Accumulate raw time */
@@ -1077,6 +1078,7 @@ static void update_wall_time(void)
 		timekeeper.xtime.tv_sec++;
 		leap = second_overflow(timekeeper.xtime.tv_sec);
 		timekeeper.xtime.tv_sec += leap;
+		timekeeper.wall_to_monotonic.tv_sec -= leap;
 	}
 
 	timekeeping_update(false);