zd1211rw: move set_multicast_hash and set_rx_filter from workers to configure_filter

Workers not needed anymore since configure_filter may sleep. Keep
mac->multicast_hash for later use (hw reset).

Signed-off-by: Jussi Kivilinna <jussi.kivilina@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>