coresight-etm: unlock on error paths in mode_store()

There are some missing unlocks on the error paths.

Fixes: a939fc5a ('coresight-etm: add CoreSight ETM/PTM driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/coresight/coresight-etm3x.c

@@ -573,7 +573,8 @@ static ssize_t mode_store(struct device *dev,
 	if (drvdata->mode & ETM_MODE_STALL) {
 		if (!(drvdata->etmccr & ETMCCR_FIFOFULL)) {
 			dev_warn(drvdata->dev, "stall mode not supported\n");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_unlock;
 		}
 		drvdata->ctrl |= ETMCR_STALL_MODE;
 	 } else
@@ -582,7 +583,8 @@ static ssize_t mode_store(struct device *dev,
 	if (drvdata->mode & ETM_MODE_TIMESTAMP) {
 		if (!(drvdata->etmccer & ETMCCER_TIMESTAMP)) {
 			dev_warn(drvdata->dev, "timestamp not supported\n");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_unlock;
 		}
 		drvdata->ctrl |= ETMCR_TIMESTAMP_EN;
 	} else
@@ -595,6 +597,10 @@ static ssize_t mode_store(struct device *dev,
 	spin_unlock(&drvdata->spinlock);
 
 	return size;
+
+err_unlock:
+	spin_unlock(&drvdata->spinlock);
+	return ret;
 }
 static DEVICE_ATTR_RW(mode);