Subject: [PATCH v2] i40e: workaround for XL710 performance

On XL710, performance number is far from the expectation on recent firmware
versions, if promiscuous mode is disabled, or promiscuous mode is enabled and
port MAC address is equal to the packet destination MAC address. The fix for
this issue may not be integrated in the following firmware version. So the
workaround in software driver is needed. For XL710, it needs to modify the
initial values of 3 internal only registers, which are the same as X710.
Note that the values for X710 and XL710 registers could be different, and the
workaround can be removed when it is fixed in firmware in the future.

Signed-off-by: Helin Zhang <redacted>

Acked-by: Jingjing Wu <redacted>

---
 lib/librte_pmd_i40e/i40e_ethdev.c | 44
++++++++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 14 deletions(-)

v2 changes:
* Supported modifying the address of 0x269FBC of XL710 during
  initialization, to fix the minor performance gap to expectation.
  That means XL710 can meet the performance expectation with this
  workaround.

Applied. Thanks to Neil's for his reviewing efforts on v1 version!

Thanks,
Helin