amd-xgbe: Update connection validation for backplane mode

Update the connection type enumeration for backplane mode and return
an error when there is a mismatch between the mode and the connection
type.

Signed-off-by: Tom Lendacky <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c

···
 	XGBE_CONN_TYPE_NONE = 0,
 	XGBE_CONN_TYPE_SFP,
 	XGBE_CONN_TYPE_MDIO,
+	XGBE_CONN_TYPE_RSVD1,
 	XGBE_CONN_TYPE_BACKPLANE,
 	XGBE_CONN_TYPE_MAX,
 };
···
 	if (xgbe_phy_conn_type_mismatch(pdata)) {
 		dev_err(pdata->dev, "phy mode/connection mismatch (%#x/%#x)\n",
 			phy_data->port_mode, phy_data->conn_type);
+		return -EINVAL;
 	}
 
 	/* Validate the mode requested */