media: bcm2835-unicam: Fix reference counting in unicam_open

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

The reference counting of node->open was only incremented after
a check that the node was v4l2_fh_is_singular_file, which resulted
in the counting going wrong and s_power not being called at an
appropriate time.
Signed-off-by: NDave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/media/platform/bcm2835/bcm2835-unicam.c

@@ -2170,16 +2170,18 @@ static int unicam_open(struct file *file)
 		goto unlock;
 	}
 
+	node->open++;
+
 	if (!v4l2_fh_is_singular_file(file))
 		goto unlock;
 
 	ret = v4l2_subdev_call(dev->sensor, core, s_power, 1);
 	if (ret < 0 && ret != -ENOIOCTLCMD) {
 		v4l2_fh_release(file);
+		node->open--;
 		goto unlock;
 	}
 
-	node->open++;
 	ret = 0;
 
 unlock: