Staging: wlan-ng: p80211netdev.c fix netdev alloc to prevent oops on device start

a version of this patch is in the wlan-ng_devel tree

initializes netdev correctly to prevent an oops on device start.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>