usb: gadget: export composite's setup & disconnect function

The configfs can't use all of composite's hooks because ->bind() and
->unbind() has to be done a little differently. ->disconnect() and
->setup() on the hand can be recycled.
This patch exports them both so configfs can use them.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/composite.c

@@ -1077,7 +1077,7 @@ static void composite_setup_complete(struct usb_ep *ep, struct usb_request *req)
  * housekeeping for the gadget function we're implementing.  Most of
  * the work is in config and function specific setup.
  */
-static int
+int
 composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
@@ -1344,7 +1344,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 	return value;
 }
 
-static void composite_disconnect(struct usb_gadget *gadget)
+void composite_disconnect(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
 	unsigned long			flags;

include/linux/usb/composite.h

@@ -398,6 +398,10 @@ extern int usb_string_ids_tab(struct usb_composite_dev *c,
 			      struct usb_string *str);
 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
 
+extern void composite_disconnect(struct usb_gadget *gadget);
+extern int composite_setup(struct usb_gadget *gadget,
+		const struct usb_ctrlrequest *ctrl);
+
 /*
  * Some systems will need runtime overrides for the  product identifiers
  * published in the device descriptor, either numbers or strings or both.