ixgbe: Fix limitations on macvlan so we can support up to 63 offloaded devices

This change is a fix of the macvlan offload so that we correctly handle
macvlan offloaded devices. Specifically we were configuring our limits based
on the assumption that we were going to max out the RSS indices for every
mode. As a result when we went to 15 or more macvlan interfaces we were
forced into the 2 queue RSS mode on VFs even though they could have still
supported 4.

This change splits the logic up so that we limit either the total number of
macvlan instances if DCB is enabled, or limit the number of RSS queues used
per macvlan (instead of per pool) if SR-IOV is enabled. By doing this we
can make best use of the part.

In addition I have increased the maximum number of supported interfaces to
63 with one queue per offloaded interface as this more closely reflects the
actual values supported by the interface.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>