i40e: Do not disable/enable FCoE VSI with DCB reconfig

FCoE VSI Tx queue disable times out when reconfiguring as a result of
DCB TC configuration change event.

The hardware allows us to skip disabling and enabling of Tx queues for
VSIs with single TC enabled. As FCoE VSI is configured to have only
single TC we skip it from disable/enable flow.

Change-ID: Ia73ff3df8785ba2aa3db91e6f2c9005e61ebaec2
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Tested-By: Jack Morgan <jack.morgan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>