V4L/DVB (7036): radio: Use video_device_release rather than kfree

The file drivers/media/video/videodev.c defines both video_device_alloc and
video_device_release.  These are essentially just kzmalloc and kfree,
respectively, but it seems better to use video_device_release, as done in
the other media files, rather than kfree, in case the implementation some
day changes.

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: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/radio/radio-maestro.c

@@ -423,7 +423,7 @@ static int __devinit maestro_probe(struct pci_dev *pdev,
 errunr:
 	video_unregister_device(maestro_radio_inst);
 errfr1:
-	kfree(maestro_radio_inst);
+	video_device_release(maestro_radio_inst);
 errfr:
 	kfree(radio_unit);
 err: