net/mlx5: DR, Remove redundant vport number from action

The vport number is part of the vport_cap, there is no reason
to store in a separate variable on the vport.

Fixes: 9db810ed ("net/mlx5: DR, Expose steering action functionality")
Signed-off-by: Alex Vesker <valex@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>