Clock struct is part of struct mlx5_core_dev. Code was inconsistent, on
some cases used container_of and on another used clock->mdev.

Align code to use container_of amd remove clock->mdev pointer.
While here, fix reverse xmas tree coding style.
Signed-off-by: NEran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: NMoshe Shemesh <moshe@mellanox.com>