media: i2c: mt9m001: Drop check for reentrant .s_stream()

The subdev .s_stream() operation shall not be called to start streaming
on an already started subdev, or stop streaming on a stopped subdev.
Remove the check that guards against that condition.

The streaming field of the driver's private structure is now unused,
drop it as well.

Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/i2c/mt9m001.c

···
 		struct v4l2_ctrl *autoexposure;
 		struct v4l2_ctrl *exposure;
 	};
-	bool streaming;
 	struct mutex mutex;
 	struct v4l2_rect rect;	/* Sensor window */
 	struct clk *clk;
···
 
 	mutex_lock(&mt9m001->mutex);
 
-	if (mt9m001->streaming == enable)
-		goto done;
-
 	if (enable) {
 		ret = pm_runtime_resume_and_get(&client->dev);
 		if (ret < 0)
···
 		pm_runtime_put(&client->dev);
 	}
 
-	mt9m001->streaming = enable;
-done:
 	mutex_unlock(&mt9m001->mutex);
 
 	return 0;