net/mlx5: DR, Fix vport number data type to u16

According to the HW spec, vport number is a 16-bit value.
Fix vport usage all over the code to u16 data type.

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Muhammad Sammar <muhammads@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>