media: verisilicon: Move Rockchip AV1 hardware drivers to the corresponding option

There is no need to compile the Rockchip specific AV1 drivers if
CONFIG_VIDEO_HANTRO_ROCKCHIP is not set.
All the driver functions are only referenced by rockchip_vpu_hw.c which
is already under this option.

Fixes: 727a4006 ("media: verisilicon: Add Rockchip AV1 decoder")
Fixes: d8ebe59e ("media: verisilicon: Add film grain feature to AV1 driver")
Fixes: c0d0e579 ("media: verisilicon: Add AV1 entropy helpers")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>