rndis_wlan: reset device and restore multicast list on rndis_wlan_reset()

Reset device properly with RNDIS_MSG_RESET in rndis_wlan_reset() and restore
multicast list afterwards.

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