brcmfmac: dont use ZERO flag for usb IN

URB_ZERO_PACKET should only be set or bulk OUT and this condition
is checked with a WARN_ON in usb_submit_urb(). This patch fixes
brcmfmac to get rid of this warning filling the logs.
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/usb.c

@@ -581,7 +581,6 @@ static void brcmf_usb_rx_refill(struct brcmf_usbdev_info *devinfo,
 	usb_fill_bulk_urb(req->urb, devinfo->usbdev, devinfo->rx_pipe,
 			  skb->data, skb_tailroom(skb), brcmf_usb_rx_complete,
 			  req);
-	req->urb->transfer_flags |= URB_ZERO_PACKET;
 	req->devinfo = devinfo;
 
 	ret = usb_submit_urb(req->urb, GFP_ATOMIC);