net/mlx5e: Expose ethtool pause and link functions to mlx5e callers

Towards supporting set/get of global pause for the port
and get of the port link ksetting from the uplink representor,
expose the relevant entries to other mlx5 callers.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>