qed: Prevent over-usage of vlan credits by PF

Each PF/VF has a limited number of vlan filters for
configuration purposes; This information is passed to qede
and is used to prevent over-usage - once a vlan is to be
configured and no filter credit is available, the driver
would switch into working in vlan-promisc mode.

Problem is the credit pool is shared by both PFs and VFs,
and currently PFs aren't deducting the filters that are
reserved for their VFs from their quota, which may lead
to some vlan filters failing unknowingly due to lack of credit.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>