ixgbe: Fix VLAN promisc in relation to SR-IOV

ixgbe: Fix VLAN promisc in relation to SR-IOV

BugLink: http://bugs.launchpad.net/bugs/1536473
This patch is a follow-on for enabling VLAN promiscuous and allowing the PF
to add VLANs without adding a VLVF entry.  What this patch does is go
through and free the VLVF registers if they are not needed as the VLAN
belongs only to the PF which is the default pool.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit e1d0a2af2b30f5f0cbce2e4dd438d4da2433b226)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>