media: staging: allegro: fix broken registration of controls

Since commit cc62c747 ("media: allegro: add missed checks in
allegro_open()") the allegro device does provide v4l2 controls to user
space anymore. The reason is that v4l2_fh_init() initializes
fh->ctrl_handler to vdev->ctrl_handler, which invalidates the previous
driver override of the ctrl_handler.

Therefore, v4l2_fh_init() must be called before the driver overrides the
fh->ctrl_handler with its own handler.

Move the initialization of the fh back to the top, as the initialization
does not does not need to be reverted on errors, but it is enough to
free the channel.

Fixes: cc62c747 ("media: allegro: add missed checks in allegro_open()")
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/allegro-dvt/allegro-core.c

@@ -2276,6 +2276,8 @@ static int allegro_open(struct file *file)
 	if (!channel)
 		return -ENOMEM;
 
+	v4l2_fh_init(&channel->fh, vdev);
+
 	init_completion(&channel->completion);
 
 	channel->dev = dev;
@@ -2348,7 +2350,6 @@ static int allegro_open(struct file *file)
 		goto error;
 	}
 
-	v4l2_fh_init(&channel->fh, vdev);
 	file->private_data = &channel->fh;
 	v4l2_fh_add(&channel->fh);