net: phy: micrel: Fix link-up failure at boot time

At boot time the link not come up if it was not already set by
U-Boot. The cable needed to be unplugged and then plugged again to
make the link come up.

This issue is caused by the Micrel KSZ9031 PHY which may fail to
establish a link when the Asymmetric Pause capability is set, as
described in a Silicon Errata (DS80000691D or DS80000692D), which
advises to always disable the capability.

This was fixed in mainline by 3aed3e2 ("net: phy: micrel: add
Asym Pause workaround"). But this patch doesn't apply on a 4.19 kernel
and need to be adapted to the old framework.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

Author: gclement

drivers/net/phy/micrel.c

@@ -973,7 +973,7 @@ static struct phy_driver ksphy_driver[] = {
 	.phy_id		= PHY_ID_KSZ9031,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
 	.name		= "Micrel KSZ9031 Gigabit PHY",
-	.features	= PHY_GBIT_FEATURES,
+	.features	= PHY_GBIT_FEATURES | SUPPORTED_Pause,
 	.flags		= PHY_HAS_INTERRUPT,
 	.driver_data	= &ksz9021_type,
 	.probe		= kszphy_probe,