brcmfmac: fix race condition for rx and tx data.

brcmfmac: fix race condition for rx and tx data.

On both rx and tx there is was a race condition on the queueing
of usb requests. When for example frame gets submitted it is
possible that complete function gets called even before
usb_submit_urb() returns. As a result it is possible that usb
requests get losts, which was noticed on OMAP4 pandaboard
platform. This patch fixes the race condition.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
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>