i40e: Collect PFC XOFF RX stats even in single TC case

i40e: Collect PFC XOFF RX stats even in single TC case

Orabug: 21570582

When PFC is enabled for any UP in single TC configuration the driver didn't
collect the PFC XOFF RX stats. Though a single TC with PFC enabled is not a
common scenario do not prevent the driver from collecting stats if firmware
indicates that PFC is enabled.

Change-ID: Ie20bd58b07608b528f3c6d95894c9ae56b00077a
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit e120814d74bc805769d18ed7177f43a17a88fd40)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>