brcm80211: smac: resume transmit fifo upon receiving frames

brcm80211: smac: resume transmit fifo upon receiving frames

commit badc4f07622f0f7093a201638f45e85765f1b5e4 upstream.

There have been reports about not being able to use access-points
on channel 12 and 13 or having connectivity issues when these channels
were part of the selected regulatory domain. Upon switching to these
channels the brcmsmac driver suspends the transmit dma fifos. This
patch resumes them upon handing over the first received beacon to
mac80211.

This patch is to be applied to the stable tree for kernel versions
3.2 and 3.3.

Tested-by: Francesco Saverio Schiavarelli <fschiava@libero.it>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>