vlan-id is wrongly getting as 0 when PFC is enabled.
Set vlan-id configured by user in QP parameters.
In case vlan interface is not used, flash a warning to
user to configure vlan and assign vlan-id as 0 in qp params.

Fixes: dbf727de ('IB/core: Use GID table in AH creation and dmac resolution')
Cc: Matan Barak <matanb@mellanox.com>
Signed-off-by: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>