ixgbe: dcb: use DCB config values for FCoE traffic class on open

Disabling and enabling DCB can cause FCoE hardware initialization to
occur on the incorrect traffic class when the up2tc mapping has not
yet been reconfigured.

Fix this by using the DCB configuration maps that are correct
and will be pushed at mqprio after DCB driver setup completes
successfully.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Marcus Dennis <marcusx.e.dennis@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>