dt-bindings: media: mediatek,vcodec: Fix addressing cell sizes

'dma-ranges' in the example is written for cell sizes of 2 cells, but
the schema and example specify sizes of 1 cell. As the h/w has a bus
address of >32-bits, cell sizes of 2 is correct. Update the schema's
'#address-cells' and '#size-cells' to be 2 and adjust the example
throughout.

There's no error currently because dtc only checks 'dma-ranges' is a
correct multiple number of cells (3) and the schema checking is based on
bracketing of entries.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220301233501.2110047-1-robh@kernel.org