Merge branch 'mlxsw-ecn-marking'

Ido Schimmel says:

====================
mlxsw: spectrum: Fix ECN marking in tunnel decapsulation

Patch #1 fixes a discrepancy between the software and hardware data
paths with regards to ECN marking after decapsulation. See the changelog
for a detailed description.

Patch #2 extends the ECN decap test to cover all possible combinations
of inner and outer ECN markings. The test passes over both data paths.

v2:
* Only set ECT(1) if inner is ECT(0)
* Introduce a new helper to determine inner ECN. Share it between NVE
  and IP-in-IP tunnels
* Extend the selftest
====================

Signed-off-by: David S. Miller <davem@davemloft.net>