Merge branch 'sfc-ptp'

Edward Cree says:

====================
sfc: add support for PTP over IPv6 and 802.3
Most recent cards (8000 series and newer) had enough hardware support
for this, but it was not enabled in the driver. The transmission of PTP
packets over these protocols was already added in commit bd4a2697
("sfc: use hardware tx timestamps for more than PTP"), but receiving
them was already unsupported so synchronization didn't happen.

These patches add support for timestamping received packets over
IPv6/UPD and IEEE802.3.

v2: fixed weird indentation in efx_ptp_init_filter
v3: fixed bug caused by usage of htons in PTP_EVENT_PORT definition.
    It was used in more places, where htons was used too, so using it
    2 times leave it again in host order. I didn't detected it in my
    tests because it only affected if timestamping through the MC, but
    the model I used do it through the MAC. Detected by kernel test
    robot <lkp@intel.com>
v4: removed `inline` specifiers from 2 local functions
v5: restored deleted comment with useful explanation about packets
    reordering. Deleted useless whitespaces.
====================

Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>