fotg210-udc: Add missing completion handler

This is used when responding to GET_STATUS requests. Without this, it
crashes on completion.

Fixes: b84a8dee ("usb: gadget: add Faraday fotg210_udc driver")
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230123073508.2350402-2-linus.walleij@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/fotg210/fotg210-udc.c

@@ -709,6 +709,20 @@ static int fotg210_is_epnstall(struct fotg210_ep *ep)
 	return value & INOUTEPMPSR_STL_EP ? 1 : 0;
 }
 
+/* For EP0 requests triggered by this driver (currently GET_STATUS response) */
+static void fotg210_ep0_complete(struct usb_ep *_ep, struct usb_request *req)
+{
+	struct fotg210_ep *ep;
+	struct fotg210_udc *fotg210;
+
+	ep = container_of(_ep, struct fotg210_ep, ep);
+	fotg210 = ep->fotg210;
+
+	if (req->status || req->actual != req->length) {
+		dev_warn(&fotg210->gadget.dev, "EP0 request failed: %d\n", req->status);
+	}
+}
+
 static void fotg210_get_status(struct fotg210_udc *fotg210,
 				struct usb_ctrlrequest *ctrl)
 {
@@ -1253,6 +1267,8 @@ int fotg210_udc_probe(struct platform_device *pdev, struct fotg210 *fotg)
 	if (fotg210->ep0_req == NULL)
 		goto err_map;
 
+	fotg210->ep0_req->complete = fotg210_ep0_complete;
+
 	fotg210_init(fotg210);
 
 	fotg210_disable_unplug(fotg210);