net/mlx5: E-Switch, Make vport number u16

Vport number is 16-bit field in hardware. Make it u16.

Move location of vport in the structure so that it reduces a hole
in the structure.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>