net/mlx5: Lock mlx5 devlink health recovery callback

Change devlink instance locks in mlx5 driver to have devlink health
recovery callback locked, while keeping all driver paths which lead to
devl_ API functions called by the driver locked.

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