ipc/mqueue.c: delete an unnecessary check before the macro call dev_kfree_skb()

dev_kfree_skb() input parameter validation, thus the test around the call
is not needed.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/07477187-63e5-cc80-34c1-32dd16b38e12@web.deSigned-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/mqueue.c

@@ -1333,7 +1333,7 @@ static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
 out:
 	if (sock)
 		netlink_detachskb(sock, nc);
-	else if (nc)
+	else
 		dev_kfree_skb(nc);
 
 	return ret;