usb: gadget: rndis: don't test against req->length

composite.c always sets req->length to zero
and expects function driver's setup handlers
to return the amount of bytes to be used
on req->length. If we test against req->length
w_length will always be greater than req->length
thus making us always stall that particular
SEND_ENCAPSULATED_COMMAND request.

Tested against a Windows XP SP3.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/f_rndis.c

@@ -420,8 +420,7 @@ rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 	 */
 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 			| USB_CDC_SEND_ENCAPSULATED_COMMAND:
-		if (w_length > req->length || w_value
-				|| w_index != rndis->ctrl_id)
+		if (w_value || w_index != rndis->ctrl_id)
 			goto invalid;
 		/* read the request; process it later */
 		value = w_length;