net/mlx5: Fix wrong limitation of metadata match on ecpf

Match metadata support check returns false for ecpf device.
However, this support does exist for ecpf and therefore this
limitation should be removed to allow feature such as stacked
devices and internal port offloaded to be supported.

Fixes: 92ab1eb3

 ("net/mlx5: E-Switch, Enable vport metadata matching if firmware supports it")
Signed-off-by: Ariel Levkovich <lariel@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>