tg3: convert EEE handling to use linkmode bitmaps

tg3: convert EEE handling to use linkmode bitmaps

Convert EEE handling to use linkmode bitmaps. This prepares for
removing the legacy bitmaps from struct ethtool_keee.
No functional change intended.

Note: The change to mii_eee_cap1_mod_linkmode_t(tp->eee.advertised, val)
in tg3_phy_autoneg_cfg() isn't completely obvious, but it doesn't change
the current functionality.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/0652b910-6bcc-421f-8769-38f7dae5037e@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>