MAINTAINERS: merge sections for ROCKCHIP VIDEO DECODER DRIVER

Commit d968e50b5c26 ("media: rkvdec: Unstage the driver") moves the driver
from staging/media/ to media/platform/rockchip/ and adds a new section
ROCKCHIP RKVDEC VIDEO DECODER DRIVER in MAINTAINERS. It seems that it was
overlooked that the section ROCKCHIP VIDEO DECODER DRIVER in MAINTAINERS
already existed, referring to the same files before the driver was moved
as the new section refers to after the driver was moved.

So, merge the information from the two sections for ROCKCHIP (RKVDEC) VIDEO
DECODER DRIVER into one. This essentially results in adding the maintainer
of the previously existing section in the new section and then removing
that previously existing section.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>