staging: most: usb: don't set URB_ZERO_PACKET flag for synchronous data

This patch avoids setting the URB_ZERO_PACKET transfer flag for synchronous
data. This is needed to prevent the host from sending an empty packet when
data is aligned to an endpoint packet boundary.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/usb/usb.c

@@ -592,7 +592,8 @@ static int hdm_enqueue(struct most_interface *iface, int channel,
 				  length,
 				  hdm_write_completion,
 				  mbo);
-		if (conf->data_type != MOST_CH_ISOC)
+		if (conf->data_type != MOST_CH_ISOC &&
+		    conf->data_type != MOST_CH_SYNC)
 			urb->transfer_flags |= URB_ZERO_PACKET;
 	} else {
 		usb_fill_bulk_urb(urb, mdev->usb_device,