net: stmmac: remove PCS "mode" pause handling

net: stmmac: remove PCS "mode" pause handling

Remove the "we always autoneg pause" forcing when the stmmac driver
decides that a "PCS" is present, which blocks passing the ethtool
pause calls to phylink when using SGMII mode.

This prevents the pause results being reported when a PHY is attached
using SGMII mode, or the pause settings being changed in SGMII mode.
There is no reason to prevent this.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/E1v9P6D-0000000AolU-2zjv@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>