Add mediatek,mt8186-jpgenc compatible to binding document.

MT8186 iommu support 0~16GB iova. We separate it to four banks:
0~4G; 4G~8G; 8G~12G; 12G~16G.

The "dma-ranges" could be used to adjust the bank we locate.
If we don't set this property. The default range always is 0~4G.
Signed-off-by: kyrie wu <kyrie.wu@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>