[PATCH] zd1211rw: monitor all packets

While in monitor mode the zd1211rw received only a limited
set of packets. This patch forwards now all packets the device
receives. Notify that while monitoring no FCS checks are done; so
strange packets might appear in the network sniffer of your
choice.

ATTENTION: Support for multiple interfaces on a single ZD1211
device is currently broken. So this code works only on the first
interface.

Here is an example to put the device in monitor mode.

iwconfig wlan0 mode monitor
ifconfig wlan0 up
iwconfig wlan0 channel 10

[dsd@gentoo.org: backport to mainline]
Signed-off-by: Ulrich Kunitz <kune@deine-taler.de>
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>