Use the dma_set_mask_and_coherent helper to set vdec
DMA bit mask to support 34bits iova space(16GB) that
the mt8192 iommu HW support.

Whole the iova range separate to 0~4G/4G~8G/8G~12G/12G~16G,
regarding which iova range VDEC actually locate, it
depends on the dma-ranges property of vdec dtsi node.
Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>