bcmdhd: filter multicast packages while suspended, in some crowded WLANs, with a lot of multicast packages circulating,
the device would not enter deep sleep. this will allow the device to enter deep sleep, credits to abmantis

Change-Id: Ie9cad333c24edd79aa874ae0cbb5a1ae70a2b276
Signed-off-by: zwliew <zhaoweiliew@gmail.com>