mlxsw: switchx2: Add eth prefix to port create and remove

Since we are about to add Infiniband port remove and create we will add
"eth" prefix to port create and remove APIs.

Signed-off-by: Elad Raz <eladr@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>