net: dsa: mv88e6xxx: Release lock while requesting IRQ

There is no need to hold the register lock while requesting the GPIO
interrupt. By not holding it we can also avoid a false positive
lockdep splat.
Reported-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -456,10 +456,12 @@ static int mv88e6xxx_g1_irq_setup(struct mv88e6xxx_chip *chip)
 	 */
 	irq_set_lockdep_class(chip->irq, &lock_key, &request_key);
 
+	mutex_unlock(&chip->reg_lock);
 	err = request_threaded_irq(chip->irq, NULL,
 				   mv88e6xxx_g1_irq_thread_fn,
 				   IRQF_ONESHOT | IRQF_SHARED,
 				   dev_name(chip->dev), chip);
+	mutex_lock(&chip->reg_lock);
 	if (err)
 		mv88e6xxx_g1_irq_free_common(chip);