ixgbe: change handling of multicast filters

In line with changes done by Alex Duyck regarding unicast filters, we
now only set multicast filters when the interface is not in promiscuous
mode for multicast packets. This also has an impact on the RAR usage
such that SR-IOV has some RARs reserved for its own usage.

Reported-by: Alex Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>