The underlying hardware may or may not allow reading of the head or tail
registers and it really makes no difference if we use the software
cached values. So, always used the software cached values.

Fixes: 9c6c1259 ("i40e: Detection and recovery of TX queue hung logic moved to service_task from tx_timeout")
Signed-off-by: NBrett Creeley <brett.creeley@intel.com>
Co-developed-by: NNorbert Zulinski <norbertx.zulinski@intel.com>
Signed-off-by: NNorbert Zulinski <norbertx.zulinski@intel.com>
Signed-off-by: NMateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: NKonrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>