Merge branch 'mlxsw-spectrum'

Jiri Pirko says:

====================
mlxsw: Driver update, add initial support for Spectrum ASIC

Purpose of this patchset is to introduce initial support for Mellanox
Spectrum ASIC, including L2 bridge forwarding offload.

The only non-mlxsw patch in this patchset is the first one, introducing
pre-change upper notifier. That is used in last patch to ensure ports of
single ASIC are not bridged into multiple bridges, as that scenario is
currently not supported by driver.
====================

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