usb: dwc3: move gadget prototypes to core.h

host prototypes are there, let's move gadget's
closer.
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.h

@@ -791,4 +791,7 @@ union dwc3_event {
 int dwc3_host_init(struct dwc3 *dwc);
 void dwc3_host_exit(struct dwc3 *dwc);
 
+int dwc3_gadget_init(struct dwc3 *dwc);
+void dwc3_gadget_exit(struct dwc3 *dwc);
+
 #endif /* __DRIVERS_USB_DWC3_CORE_H */

drivers/usb/dwc3/gadget.h

@@ -110,9 +110,6 @@ static inline void dwc3_gadget_move_request_queued(struct dwc3_request *req)
 	list_move_tail(&req->list, &dep->req_queued);
 }
 
-int dwc3_gadget_init(struct dwc3 *dwc);
-void dwc3_gadget_exit(struct dwc3 *dwc);
-
 void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		int status);