usb: dwc3: ep0: add a default case for SetFeature command

Without this default case returning an error,
thus replying with a stall, we would fail
USB30CV TD 9.11 Bad Feature test case.

Cc: stable@vger.kernel.org
Signed-off-by: Gerard Cauvy <g-cauvy1@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/ep0.c

@@ -353,6 +353,9 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 
 			dwc->test_mode_nr = wIndex >> 8;
 			dwc->test_mode = true;
+			break;
+		default:
+			return -EINVAL;
 		}
 		break;