regulator: core: Use ww_mutex for regulators locking

Wait/wound mutex shall be used in order to avoid lockups on locking of
coupled regulators.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Suggested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/wm8350-regulator.c

@@ -1153,7 +1153,7 @@ static irqreturn_t pmic_uv_handler(int irq, void *data)
 {
 	struct regulator_dev *rdev = (struct regulator_dev *)data;
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock(rdev);
 	if (irq == WM8350_IRQ_CS1 || irq == WM8350_IRQ_CS2)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_REGULATION_OUT,
@@ -1162,7 +1162,7 @@ static irqreturn_t pmic_uv_handler(int irq, void *data)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_UNDER_VOLTAGE,
 					      NULL);
-	mutex_unlock(&rdev->mutex);
+	regulator_unlock(rdev);
 
 	return IRQ_HANDLED;
 }