sched: Remove noop in lowest_flag_domain()

Checking for the validity of sd is removed, since it is already
checked by the for_each_domain macro.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTimT+Tut-3TshCDm-NiLLXrOznibNA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -3660,7 +3660,7 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
 	struct sched_domain *sd;
 
 	for_each_domain(cpu, sd)
-		if (sd && (sd->flags & flag))
+		if (sd->flags & flag)
 			break;
 
 	return sd;