net/ixgbe: fix PF DCB info

net/ixgbe: fix PF DCB info

When SRIOV is active, the function ixgbe_dev_get_dcb_info( )
should return the DCB traffic class info of its own queues,
not including any DCB info of the queues of any its VF.

When VMDQ is active, all queues are belonged to the PF,
the function ixgbe_dev_get_dcb_info can return DCB info
of all queues.

Fixes: 89d6728c7837 ("ethdev: get DCB information")
Cc: stable@dpdk.org
Signed-off-by: Wei Dai <wei.dai@intel.com>
Reviewed-by: Jingjing Wu <jingjing.wu@intel.com>