net/mlx5e: Fix ethtool indication of connector type

[ Upstream commit 3211434d ]

Use connector_type read from PTYS register when it's valid, based on
corresponding capability bit.

Fixes: 5b4793f8

 ("net/mlx5e: Add support for reading connector type from PTYS")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Eran Ben Elisha <eranbe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>