media: rockchip/vpu: Support the Request API

Introduce support for the Request API. Although the JPEG encoder
does not mandate using the Request API, it's perfectly possible to
use it, if the application wants to.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>