rescounter: remove __must_check from res_counter_charge_nofail()

Since we will succeed with the allocation no matter what, there isn't a
need to use __must_check with it.  It can very well be optional.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ying Han <yinghan@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/res_counter.h

@@ -119,7 +119,7 @@ int __must_check res_counter_charge_locked(struct res_counter *counter,
 					   unsigned long val, bool force);
 int __must_check res_counter_charge(struct res_counter *counter,
 		unsigned long val, struct res_counter **limit_fail_at);
-int __must_check res_counter_charge_nofail(struct res_counter *counter,
+int res_counter_charge_nofail(struct res_counter *counter,
 		unsigned long val, struct res_counter **limit_fail_at);
 
 /*