mfd: Don't open-code mc13xxx_unlock

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
index a2ac2ed..b9fcaf0 100644
--- a/drivers/mfd/mc13xxx-core.c
+++ b/drivers/mfd/mc13xxx-core.c
@@ -749,7 +749,7 @@
 	if (ret) {
 err_mask:
 err_revision:
-		mutex_unlock(&mc13xxx->lock);
+		mc13xxx_unlock(mc13xxx);
 		dev_set_drvdata(&spi->dev, NULL);
 		kfree(mc13xxx);
 		return ret;