Merge branch 'ethtool-mm-api-consolidation'

Vladimir Oltean says:

====================
ethtool mm API consolidation

This series consolidates the behavior of the 2 drivers that implement
the ethtool MAC Merge layer by making NXP ENETC commit its preemptible
traffic classes to hardware only when MM TX is active (same as Ocelot).

Then, after resolving an issue with the ENETC driver, it restricts user
space from entering 2 states which don't make sense:

- pmac-enabled off tx-enabled on  verify-enabled *
- pmac-enabled *   tx-enabled off verify-enabled on

Then, it introduces a selftest (ethtool_mm.sh) which puts everything
together and tests all valid configurations known to me.

This is simultaneously the v2 of "[PATCH net-next 0/2] ethtool mm API
improvements":
https://lore.kernel.org/netdev/20230415173454.3970647-1-vladimir.oltean@nxp.com/
which had caused some problems to openlldp. Those were solved in the
meantime, see:
https://github.com/intel/openlldp/commit/11171b474f6f3cbccac5d608b7f26b32ff72c651

and of "[RFC PATCH net-next] selftests: forwarding: add a test for MAC
Merge layer":
https://lore.kernel.org/netdev/20230210221243.228932-1-vladimir.oltean@nxp.com/
====================

Link: https://lore.kernel.org/r/20230418111459.811553-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>