i40e: Only enable TC0 for NIC partition type

In case of MFP mode the driver was returning incorrect number of TCs
for partitions that are not enabled for iSCSI. Though the driver does
not configure these TCs in the Tx scheduler for the NIC partitions;
it does use this map to setup the queue mappings.

This patch fixes this and keeps all the NIC partitions to the default
PF TC i.e. TC0.

Change-ID: Iede214c907e7bac1356e999049b9f642759512b3
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>