[media] MEDIA: ttusbir, fix double free

rc_unregister_device already calls rc_free_device to free the passed
device. But in one of ttusbir's probe fail paths, we call
rc_unregister_device _and_ rc_free_device. This is wrong and results
in a double free.
Instead, set rc to NULL resulting in rc_free_device being a noop.

Signed-off-by: Jiri Slaby <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/rc/ttusbir.c

···
 	return 0;
 out3:
 	rc_unregister_device(rc);
+	rc = NULL;
 out2:
 	led_classdev_unregister(&tt->led);
 out: