brcmfmac: initialize oob irq data before request_irq()

This fixes spin-forever in irq handler when IRQ is already asserted
at request_irq() time.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>