Merge branch 'mlxsw-spectrum_buffers-Add-the-ability-to-query-the-CPU-ports-shared...

Merge branch 'mlxsw-spectrum_buffers-Add-the-ability-to-query-the-CPU-ports-shared-buffer'

Ido Schimmel says:

====================
mlxsw: spectrum_buffers: Add the ability to query the CPU port's shared buffer

Shalom says:

While debugging packet loss towards the CPU, it is useful to be able to
query the CPU port's shared buffer quotas and occupancy.

Patch #1 prevents changing the CPU port's threshold and binding.

Patch #2 registers the CPU port with devlink.

Patch #3 adds the ability to query the CPU port's shared buffer quotas and
occupancy.

v3:

Patch #2:
* Remove unnecessary wrapping

v2:

Patch #1:
* s/0/MLXSW_PORT_CPU_PORT/
* Assign "mlxsw_sp->ports[MLXSW_PORT_CPU_PORT]" at the end of
  mlxsw_sp_cpu_port_create() to avoid NULL assignment on error path
* Add common functions for mlxsw_core_port_init/fini()

Patch #2:
* Move "changing CPU port's threshold and binding" check to a separate
  patch
====================

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