[PATCH] prism54: fix monitor mode oops

Manually set the device of a skb for prism54 cards that are in monitor
mode as we never call eth_type_trans in that case.

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>