igb: move all multicast addresses into multicast table array

This patch moves all of the multicast addresses out of the free Receive
address registers and instead programs them all into the multicast table
array.  As a result the multicast filtering may not be as precise, but it
also greatly reduces the overhead for multicast addresses.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>