media: add Rockchip VPU JPEG encoder driver

Add a mem2mem driver for the VPU available on Rockchip SoCs.
Currently only JPEG encoding is supported, for RK3399 and RK3288
platforms.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: fix checkpatch.pl alignment warning]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>