zd1211rw: Fix beacon filter flags thinko

zd1211rw: Fix beacon filter flags thinko

We must not clear the FIF_BCN_PRBRESP_PROMISC bit in the
new_flags. The zd-driver does support sending beacons and
probe responses to the host. What the flag does is say "Send me
all beacons and probe responses". And we actually do that. We always
do that, so we ignore the case when the bit is disabled. But that is
fine. But we must not clear the flag, as that tells mac80211 that
we do not support passing beacons and probe responses to the stack.
And that's not true.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>