i40e: Fix oops at i40e_rebuild()

Setup TC before the i40e_setup_pf_switch() call.
Memory must be initialized for all the queues
before using its resources.

Previously it could be possible that a call:
xdp_rxq_info_reg(&rx_ring->xdp_rxq, rx_ring->netdev,
rx_ring->queue_index, rx_ring->q_vector->napi.napi_id);
was made with q_vector being null.

Oops could show up with the following sequence:
- no driver loaded
- FW LLDP agent is on (flag disable-fw-lldp:off)
- link is up
- DCB configured with number of Traffic Classes that will not divide
  completely the default number of queues (usually cpu cores)
- driver load
- set private flag: disable-fw-lldp:on

Fixes: 4b208eaa ("i40e: Add init and default config of software based DCB")
Fixes: b02e5a0e

 ("xsk: Propagate napi_id to XDP socket Rx path")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>