[media] sh_vou: fix memory leak on error paths in sh_vou_open()

Memory allocated for sh_vou_file is not deallocated
on error paths in sh_vou_open().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>