V4L/DVB (7035): drivers/media/common: Add missing video_device_release

Video_device_alloc returns the result of a kzalloc.  In this case, the
value is stored in a local variable which is not copied elsewhere before
the point of the error return (video_register_device does not save its
first argument anywhere if it returns a negative value).  Thus, a
video_device_release it needed before the error return.

The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
type T,T1,T2;
identifier E;
statement S;
expression x1,x2,x3;
int ret;
@@

  T E;
  ...
* E = video_device_alloc(...);
  if (E == NULL) S
  ... when != video_device_release(...,(T1)E,...)
      when != if (E != NULL) { ... video_device_release(...,(T1)E,...); ...}
      when != x1 = (T1)E
      when != E = x3;
      when any
  if (...) {
    ... when != video_device_release(...,(T2)E,...)
        when != if (E != NULL) { ... video_device_release(...,(T2)E,...); ...}
        when != x2 = (T2)E
(
*   return;
|
*   return ret;
)
  }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
CC: Oliver Endriss <o.endriss@gmx.de>
CC: Michael Hunold <michael@mihu.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/common/saa7146_fops.c

@@ -538,6 +538,7 @@ int saa7146_register_device(struct video_device **vid, struct saa7146_dev* dev,
 	// fixme: -1 should be an insmod parameter *for the extension* (like "video_nr");
 	if (video_register_device(vfd, type, -1) < 0) {
 		ERR(("cannot register v4l2 device. skipping.\n"));
+		video_device_release(vfd);
 		return -1;
 	}