net: stmmac: convert to phylink managed EEE support

net: stmmac: convert to phylink managed EEE support

Convert stmmac to use phylink managed EEE support rather than delving
into phylib:

1. Move the stmmac_eee_init() calls out of mac_link_down() and
   mac_link_up() methods into the new mac_{enable,disable}_lpi()
   methods. We leave the calls to stmmac_set_eee_pls() in place as
   these change bits which tell the EEE hardware when the link came
   up or down, and is used for a separate hardware timer. However,
   symmetrically conditionalise this with priv->dma_cap.eee.

2. Update the current LPI timer each time LPI is enabled - which we
   need for software-timed LPI.

3. With phylink managed EEE, phylink manages the receive clock stop
   configuration via phylink_config.eee_rx_clk_stop_enable. Set this
   appropriately which makes the call to phy_eee_rx_clock_stop()
   redundant.

4. From what I can work out, all supported interfaces support LPI
   signalling on stmmac (there's no restriction implemented.) It
   also appears to support LPI at all full duplex speeds at or over
   100M. Set these capabilities.

5. The default timer appears to be derived from a module parameter.
   Set this the same, although we keep code that reconfigures the
   timer in stmmac_init_phy().

6. Remove the direct call to phy_support_eee(), which phylink will do
   on the drivers behalf if phylink_config.eee_enabled_default is set.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/E1tYAEG-0014QH-9O@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>