Bluetooth: Use IS_ERR_OR_NULL for checking bt_debugfs

Make sure to use IS_ERR_OR_NULL for checking the existing of the root
debugfs dentry bt_debugfs.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index 27e936a..94d06cb 100644
--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -2154,13 +2154,6 @@
 		goto unregister;
 	}
 
-	if (bt_debugfs) {
-		rfcomm_dlc_debugfs = debugfs_create_file("rfcomm_dlc", 0444,
-				bt_debugfs, NULL, &rfcomm_dlc_debugfs_fops);
-		if (!rfcomm_dlc_debugfs)
-			BT_ERR("Failed to create RFCOMM debug file");
-	}
-
 	err = rfcomm_init_ttys();
 	if (err < 0)
 		goto stop;
@@ -2171,6 +2164,13 @@
 
 	BT_INFO("RFCOMM ver %s", VERSION);
 
+	if (IS_ERR_OR_NULL(bt_debugfs))
+		return 0;
+
+	rfcomm_dlc_debugfs = debugfs_create_file("rfcomm_dlc", 0444,
+						 bt_debugfs, NULL,
+						 &rfcomm_dlc_debugfs_fops);
+
 	return 0;
 
 cleanup: