extcon: arizona: unlock mutex on error path in arizona_micdet()

If regmap_read() failed, arizona_micdet() returns IRQ_NONE
leaving &info->lock mutex locked as opposed to all other return paths.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

drivers/extcon/extcon-arizona.c

@@ -166,6 +166,7 @@ static irqreturn_t arizona_micdet(int irq, void *data)
 	ret = regmap_read(arizona->regmap, ARIZONA_MIC_DETECT_3, &val);
 	if (ret != 0) {
 		dev_err(arizona->dev, "Failed to read MICDET: %d\n", ret);
+		mutex_unlock(&info->lock);
 		return IRQ_NONE;
 	}