mlxsw: minimal: Extend to support line card dynamic operations

Implement line card operation callbacks got_active() / got_inactive().
The purpose of these callback to create / remove line card ports after
line card is getting active / inactive.

Implement line ports_remove_selected() callback to support line card
un-provisioning flow through 'devlink'.

Add line card operation registration and de-registration APIs.

Add module offset for line card. Offset for main board iz zero.
For line card in slot #n offset is calculated as (#n - 1) multiplied by
maximum modules number.

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