clocksource: remove redundant code

Flag CLOCK_SOURCE_WATCHDOG is cleared twice.  Note clocksource_change_rating()
won't do anyting with the cs flag.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/time/clocksource.c

@@ -91,7 +91,6 @@ static void clocksource_ratewd(struct clocksource *cs, int64_t delta)
 	       cs->name, delta);
 	cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
 	clocksource_change_rating(cs, 0);
-	cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
 	list_del(&cs->wd_list);
 }