net: ethtool: Add support for 1600Gbps speed

net: ethtool: Add support for 1600Gbps speed

Add support for 1600Gbps link modes based on 200Gbps per lane [1].
This includes the adopted IEEE 802.3dj copper and optical PMDs that use
200G/lane signaling [2].

Add the following PMD types:
- KR8 (backplane)
- CR8 (copper cable)
- DR8 (SMF 500m)
- DR8-2 (SMF 2km)

These modes are defined in the 802.3dj specifications.
References:
[1] https://www.ieee802.org/3/dj/public/23_03/opsasnick_3dj_01a_2303.pdf
[2] https://www.ieee802.org/3/dj/projdoc/objectives_P802d3dj_240314.pdf

Signed-off-by: Yael Chemla <ychemla@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/1763585297-1243980-2-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>