staging: brcm80211: remove filtering of received frames

In the receive path of the brcmsmac driver probe request frames and
frames with invalid mac address fields are dropped. This is only
fine for STA mode. Anticipating coming AP and monitor mode functionality
this is unwanted behavior.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>