iommu/mediatek: Add 12G~16G support for multi domains

In mt8192, we preassign 0-4G; 4G-8G; 8G-12G for different multimedia
engines. This depends on the "dma-ranges=" in the iommu consumer's dtsi
node.

Adds 12G-16G region here. and reword the previous comment. we don't limit
which master locate in which region.

CCU still is 8G-12G. Don't change it here.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20220503071427.2285-11-yong.wu@mediatek.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>