aoe: remove unnecessary oom message

Fixes scripts/checkpatch.pl warning:
WARNING: Possible unnecessary 'out of memory' message

Remove it can help us save a bit of memory.
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/block/aoe/aoechr.c

@@ -140,10 +140,8 @@ bail:		spin_unlock_irqrestore(&emsgs_lock, flags);
 	}
 
 	mp = kmemdup(msg, n, GFP_ATOMIC);
-	if (mp == NULL) {
-		printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
+	if (!mp)
 		goto bail;
-	}
 
 	em->msg = mp;
 	em->flags |= EMFL_VALID;