net: revert partially applied PHY topology series

The series is causing issues with PHY drivers built as modules.
Since it was only partially applied and the merge window has
opened let's revert and try again for v6.11.

Revert 6916e461 ("net: phy: Introduce ethernet link topology representation")
Revert 0ec5ed6c ("net: sfp: pass the phy_device when disconnecting an sfp module's PHY")
Revert e75e4e07 ("net: phy: add helpers to handle sfp phy connect/disconnect")
Revert fdd35396 ("net: sfp: Add helper to return the SFP bus name")
Revert 841942bc

 ("net: ethtool: Allow passing a phy index for some commands")

Link: https://lore.kernel.org/all/171242462917.4000.9759453824684907063.git-patchwork-notify@kernel.org/
Link: https://lore.kernel.org/all/20240507102822.2023826-1-maxime.chevallier@bootlin.com/
Link: https://lore.kernel.org/r/20240513154156.104281-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>