Staging: cx25821: fix double unlock in medusa_video_init()

medusa_set_videostandard() takes the lock but it always drops it before
returning.

This was found with a static checker and compile tested only.  :/

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>