media: imx-mipi-csis: Don't take lock in runtime PM handlers

The runtime PM handlers don't need manual locking as

- they are serialized by the runtime PM core
- they can't race with other functions taking the same lock, as they
  don't access any data protect by that lock

Drop the locking.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Adam Ford <aford173@gmail.com> #imx8mn-beacon
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/nxp/imx-mipi-csis.c

@@ -1348,40 +1348,34 @@ static int __maybe_unused mipi_csis_runtime_suspend(struct device *dev)
 {
 	struct v4l2_subdev *sd = dev_get_drvdata(dev);
 	struct mipi_csis_device *csis = sd_to_mipi_csis_device(sd);
-	int ret = 0;
-
-	mutex_lock(&csis->lock);
+	int ret;
 
 	ret = mipi_csis_phy_disable(csis);
 	if (ret)
-		goto unlock;
+		return -EAGAIN;
 
 	mipi_csis_clk_disable(csis);
 
-unlock:
-	mutex_unlock(&csis->lock);
-
-	return ret ? -EAGAIN : 0;
+	return 0;
 }
 
 static int __maybe_unused mipi_csis_runtime_resume(struct device *dev)
 {
 	struct v4l2_subdev *sd = dev_get_drvdata(dev);
 	struct mipi_csis_device *csis = sd_to_mipi_csis_device(sd);
-	int ret = 0;
-
-	mutex_lock(&csis->lock);
+	int ret;
 
 	ret = mipi_csis_phy_enable(csis);
 	if (ret)
-		goto unlock;
-
-	mipi_csis_clk_enable(csis);
+		return -EAGAIN;
 
-unlock:
-	mutex_unlock(&csis->lock);
+	ret = mipi_csis_clk_enable(csis);
+	if (ret) {
+		mipi_csis_phy_disable(csis);
+		return ret;
+	}
 
-	return ret ? -EAGAIN : 0;
+	return 0;
 }
 
 static const struct dev_pm_ops mipi_csis_pm_ops = {