net: phy: broadcom: use auxctl reading helper in BCM54612E code

Starting with commit 5b4e2900 ("net: phy: broadcom: add
bcm54xx_auxctl_read") we have a reading helper so use it and avoid code
duplication.
It also means we don't need MII_BCM54XX_AUXCTL_SHDWSEL_MISC define as
it's the same as MII_BCM54XX_AUXCTL_SHDWSEL_MISC just for reading needs
(same value shifted by 12 bits).
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/broadcom.c

@@ -395,10 +395,8 @@ static int bcm54612e_config_aneg(struct phy_device *phydev)
 	    (phydev->interface != PHY_INTERFACE_MODE_RGMII_RXID)) {
 		u16 reg;
 
-		/* Errata: reads require filling in the write selector field */
-		bcm54xx_auxctl_write(phydev, MII_BCM54XX_AUXCTL_SHDWSEL_MISC,
-				     MII_BCM54XX_AUXCTL_MISC_RDSEL_MISC);
-		reg = phy_read(phydev, MII_BCM54XX_AUX_CTL);
+		reg = bcm54xx_auxctl_read(phydev,
+					  MII_BCM54XX_AUXCTL_SHDWSEL_MISC);
 		/* Disable RXD to RXC delay (default set) */
 		reg &= ~MII_BCM54XX_AUXCTL_MISC_RXD_RXC_SKEW;
 		/* Clear shadow selector field */

include/linux/brcmphy.h

@@ -111,7 +111,6 @@
 #define MII_BCM54XX_AUXCTL_MISC_WREN	0x8000
 #define MII_BCM54XX_AUXCTL_MISC_RXD_RXC_SKEW	0x0100
 #define MII_BCM54XX_AUXCTL_MISC_FORCE_AMDIX	0x0200
-#define MII_BCM54XX_AUXCTL_MISC_RDSEL_MISC	0x7000
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC	0x0007
 #define MII_BCM54XX_AUXCTL_SHDWSEL_READ_SHIFT	12
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_RGMII_SKEW_EN	(1 << 8)