devlink: Add devlink reload limit option

Add reload limit to demand restrictions on reload actions.
Reload limits supported:
no_reset: No reset allowed, no down time allowed, no link flap and no
          configuration is lost.

By default reload limit is unspecified and so no constraints on reload
actions are required.

Some combinations of action and limit are invalid. For example, driver
can not reinitialize its entities without any downtime.

The no_reset reload limit will have usecase in this patchset to
implement restricted fw_activate on mlx5.

Have the uapi parameter of reload limit ready for future support of
multiselection.

Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>