usb: dwc3: gadget: re-factor USB2 test mode to a function

There are some situations were we might need to
enable USB Test Modes without having access to a
Host stack. In such situations we cannot rely
solely on USB Control Messages to enable test
features.

For those cases, we will also allow test mode
to be enabled via debugfs and this patch is a
preparation for that.

Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/gadget.h

@@ -100,6 +100,8 @@ static inline void dwc3_gadget_move_request_queued(struct dwc3_request *req)
 void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		int status);
 
+int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode);
+
 void dwc3_ep0_interrupt(struct dwc3 *dwc,
 		const struct dwc3_event_depevt *event);
 void dwc3_ep0_out_start(struct dwc3 *dwc);