[PATCH] zd1211rw: Packet filter fix for managed (STA) mode

I had problems with my AVM Fritz!Box access point. It appeared
that the AP deauthorized me and the softmac didn't reconnect me.
This patch handles the problem.

Signed-off-by: Ulrich Kunitz <kune@deine-taler.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>