staging/wlan-ng: remove function declaration

Removed useless function prototype: static function p80211netdev_rx_bh()
is defined before being used.

Signed-off-by: Denis Pithon <denis.pithon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/wlan-ng/p80211netdev.c
Simple merge