net: bcmgenet: Fix EEE implementation

commit a9f31047 upstream.

We had a number of short comings:

- EEE must be re-evaluated whenever the state machine detects a link
  change as wight be switching from a link partner with EEE
  enabled/disabled

- tx_lpi_enabled controls whether EEE should be enabled/disabled for the
  transmit path, which applies to the TBUF block

- We do not need to forcibly enable EEE upon system resume, as the PHY
  state machine will trigger a link event that will do that, too

Fixes: 6ef398ea

 ("net: bcmgenet: add EEE support")
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20230606214348.2408018-1-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>