net: dsa: mv88e6xxx: Remove set but unused variable

We don't act on any errors reading registers while handling watchdog
interrupt. Since this is an interrupt handler, we cannot return such
errors. So just remove the variable.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/global2.c

@@ -876,19 +876,18 @@ static int mv88e6390_watchdog_setup(struct mv88e6xxx_chip *chip)
 
 static int mv88e6390_watchdog_action(struct mv88e6xxx_chip *chip, int irq)
 {
-	int err;
 	u16 reg;
 
 	mv88e6xxx_g2_write(chip, MV88E6390_G2_WDOG_CTL,
 			   MV88E6390_G2_WDOG_CTL_PTR_EVENT);
-	err = mv88e6xxx_g2_read(chip, MV88E6390_G2_WDOG_CTL, &reg);
+	mv88e6xxx_g2_read(chip, MV88E6390_G2_WDOG_CTL, &reg);
 
 	dev_info(chip->dev, "Watchdog event: 0x%04x",
 		 reg & MV88E6390_G2_WDOG_CTL_DATA_MASK);
 
 	mv88e6xxx_g2_write(chip, MV88E6390_G2_WDOG_CTL,
 			   MV88E6390_G2_WDOG_CTL_PTR_HISTORY);
-	err = mv88e6xxx_g2_read(chip, MV88E6390_G2_WDOG_CTL, &reg);
+	mv88e6xxx_g2_read(chip, MV88E6390_G2_WDOG_CTL, &reg);
 
 	dev_info(chip->dev, "Watchdog history: 0x%04x",
 		 reg & MV88E6390_G2_WDOG_CTL_DATA_MASK);