net: dsa: mv88e6xxx: Drop unnecessary check in mv88e6393x_serdes_erratum_4_6()

The check for lane is unnecessary, since the function is called only
with allowed lane argument.
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/serdes.c

@@ -1284,10 +1284,7 @@ static int mv88e6393x_serdes_erratum_4_6(struct mv88e6xxx_chip *chip, int lane)
 	 * It seems that after this workaround the SERDES is automatically
 	 * powered up (the bit is cleared), so power it down.
 	 */
-	if (lane == MV88E6393X_PORT0_LANE || lane == MV88E6393X_PORT9_LANE ||
-	    lane == MV88E6393X_PORT10_LANE) {
-		err = mv88e6390_serdes_read(chip, lane,
-					    MDIO_MMD_PHYXS,
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
 				    MV88E6393X_SERDES_POC, &reg);
 	if (err)
 		return err;
@@ -1301,9 +1298,6 @@ static int mv88e6393x_serdes_erratum_4_6(struct mv88e6xxx_chip *chip, int lane)
 		return err;
 
 	return mv88e6390_serdes_power_sgmii(chip, lane, false);
-	}
-
-	return 0;
 }
 
 int mv88e6393x_serdes_setup_errata(struct mv88e6xxx_chip *chip)