media: Reset file->private_data to NULL in v4l2_fh_del()

media: Reset file->private_data to NULL in v4l2_fh_del()

Multiple drivers that use v4l2_fh and call v4l2_fh_del() manually reset
the file->private_data pointer to NULL in their video device .release()
file operation handler. Move the code to the v4l2_fh_del() function to
avoid direct access to file->private_data in drivers. This requires
adding a file pointer argument to the function.

Changes to drivers have been generated with the following coccinelle
semantic patch:

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	filp->private_data = NULL;
	...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...>
}

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...
-	filp->private_data = NULL;
	...>
}

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...>
}

Manual changes have been applied to Documentation/ to update the usage
patterns, to drivers/media/v4l2-core/v4l2-fh.c to update the
v4l2_fh_del() prototype and reset file->private_data, and to
include/media/v4l2-fh.h to update the v4l2_fh_del() function prototype
and its documentation.

Additionally, white space issues have been fixed manually in
drivers/usb/gadget/function/uvc_v4l2.c

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>