USB: gadget: f_fs: functionfs_add() renamed to functionfs_bind_config()

FunctionFS had a bit unique name for function used to add it
to USB configuration.  Renamed as to match naming convention
of other functions.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/f_fs.c

@@ -1478,9 +1478,9 @@ static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
 }
 
 
-static int functionfs_add(struct usb_composite_dev *cdev,
-			  struct usb_configuration *c,
-			  struct ffs_data *ffs)
+static int functionfs_bind_config(struct usb_composite_dev *cdev,
+				  struct usb_configuration *c,
+				  struct ffs_data *ffs)
 {
 	struct ffs_function *func;
 	int ret;