media: hantro: Enable H.264 on Rockchip VDPU2

Given H.264 support for VDPU2 was just added, let's enable it.
For now, this is only enabled on platform that don't have
an RKVDEC core, such as RK3328.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Alex Bee <knaerzche@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>