blktrace: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-block@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/trace/blktrace.c

@@ -512,8 +512,6 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	dir = debugfs_lookup(buts->name, blk_debugfs_root);
 	if (!dir)
 		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
-	if (!dir)
-		goto err;
 
 	bt->dev = dev;
 	atomic_set(&bt->dropped, 0);
@@ -522,12 +520,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	ret = -EIO;
 	bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
 					       &blk_dropped_fops);
-	if (!bt->dropped_file)
-		goto err;
 
 	bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
-	if (!bt->msg_file)
-		goto err;
 
 	bt->rchan = relay_open("trace", dir, buts->buf_size,
 				buts->buf_nr, &blk_relay_callbacks, bt);