staging: brcm80211: remove unnecessary if statements from bss_info_changed

The mac80211 api callback bss_info_changed contained two placeholders
that were expected to need to be implemented. However, reading the mac80211
notes (http://wireless.kernel.org/en/developers/Documentation/mac80211/API)
shows that it is not needed as the driver honours the flags provided with
the transmit sk_buff.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>