mac80211: fix brcmfmac on brcm2708

An upstream change broke brcmfmac when loaded with modparam roamoff=1.
As we are carrying a patch that enables roamoff by default on the
brcm2708 target to improve stability, wireless is currently broken
there. Add a patch to fix brcmfmac with roamoff=1.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>