mlxsw: convert driver to use unlocked devlink API during init/fini

Prepare for devlink reload being called with devlink->lock held and
convert the mlxsw driver to use unlocked devlink API during init and
fini flows. Take devl_lock() in reload_down() and reload_up() ops in the
meantime before reload cmd is converted to take the lock itself.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_policer: Add devlink resource support

Expose via devlink-resource the maximum number of single-rate policers
and their current occupancy. Example:

$ devlink resource show pci/0000:01:00.0
...
name global_policers size 1000 unit entry dpipe_tables none
resources:
name single_rate_policers size 968 occ 0 unit entry dpipe_tables none

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_policer: Add policer core

Add common code to handle all policer-related functionality in mlxsw.
Currently, only policer for policy engines are supported, but it in the
future more policer families will be added such as CPU (trap) policers
and storm control policers.

The API allows different modules to add / delete policers and read their
drop counter.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>