usb: dwc3: gadget: fix ep->maxburst for ep0

dwc3_gadget_set_ep_config expects maxburst as incremented by 1. So, by
default initialize ep->maxburst to 1 for ep0.

Cc: <stable@vger.kernel.org>
Signed-off-by: NPratyush Anand <pratyush.anand@st.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/dwc3/gadget.c

@@ -1605,6 +1605,7 @@ static int dwc3_gadget_init_endpoints(struct dwc3 *dwc)
 
 		if (epnum == 0 || epnum == 1) {
 			dep->endpoint.maxpacket = 512;
+			dep->endpoint.maxburst = 1;
 			dep->endpoint.ops = &dwc3_gadget_ep0_ops;
 			if (!epnum)
 				dwc->gadget.ep0 = &dep->endpoint;