net: phy: convert eee_broken_modes to a linkmode bitmap

eee_broken_modes has a eee_cap1 register layout currently. This doen't
allow to flag e.g. 2.5Gbps or 5Gbps BaseT EEE as broken. To overcome
this limitation switch eee_broken_modes to a linkmode bitmap.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://patch.msgid.link/dfe0c9ff-84b0-4328-86d7-e917ebc084a1@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>