Merge branch 'mlxsw-expose-number-of-physical-ports'

Ido Schimmel says:

====================
mlxsw: Expose number of physical ports

The switch ASIC has a limited capacity of physical ports that it can
support. While each system is brought up with a different number of
ports, this number can be increased via splitting up to the ASIC's
limit.

Expose physical ports as a devlink resource so that user space will have
visibility into the maximum number of ports that can be supported and
the current occupancy. With this resource it is possible, for example,
to write generic (i.e., not platform dependent) tests for port
splitting.

Patch #1 adds the new resource and patch #2 adds a selftest.

v2:
* Add the physical ports resource as a generic devlink resource so that
  it could be re-used by other device drivers
====================

Link: https://lore.kernel.org/r/20210121131024.2656154-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>