net/mlx5: E-Switch, Add query and modify esw vport context functions

Add esw vport query and modify functions, and exposing them is needed for
enabling or disabling registers passed as metatdata to vport NIC_RX table
in slow path.

Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>