net: phy: micrel: Add KS8851 PHY support

The KS8851 has a reduced internal PHY, which is accessible through its
registers at offset 0xe4. The PHY is compatible with KS886x PHY present
in Micrel switches, including the PHY ID Low/High registers swap, which
is present both in the MAC and the switch.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/micrel.c

@@ -1389,7 +1389,7 @@ static struct phy_driver ksphy_driver[] = {
 }, {
 	.phy_id		= PHY_ID_KSZ886X,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
-	.name		= "Micrel KSZ886X Switch",
+	.name		= "Micrel KSZ8851 Ethernet MAC or KSZ886X Switch",
 	/* PHY_BASIC_FEATURES */
 	.config_init	= kszphy_config_init,
 	.suspend	= genphy_suspend,