net: bcmgenet: Fix RGMII_MODE_EN value for GENET v1/2/3

The RGMII_MODE_EN bit value was 0 for GENET versions 1 through 3, and
became 6 for GENET v4 and above, account for that difference.

Fixes: aa09677c ("net: bcmgenet: add MDIO routines")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.h

@@ -366,6 +366,7 @@ struct bcmgenet_mib_counters {
 #define  EXT_PWR_DOWN_PHY_EN		(1 << 20)
 
 #define EXT_RGMII_OOB_CTRL		0x0C
+#define  RGMII_MODE_EN_V123		(1 << 0)
 #define  RGMII_LINK			(1 << 4)
 #define  OOB_DISABLE			(1 << 5)
 #define  RGMII_MODE_EN			(1 << 6)

drivers/net/ethernet/broadcom/genet/bcmmii.c

@@ -258,7 +258,11 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 	 */
 	if (priv->ext_phy) {
 		reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
-		reg |= RGMII_MODE_EN | id_mode_dis;
+		reg |= id_mode_dis;
+		if (GENET_IS_V1(priv) || GENET_IS_V2(priv) || GENET_IS_V3(priv))
+			reg |= RGMII_MODE_EN_V123;
+		else
+			reg |= RGMII_MODE_EN;
 		bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
 	}