dt-bindings: display: amlogic, meson-dw-hdmi: convert to yaml

Now that we have the DT validation in place, let's convert the device tree
bindings for the Amlogic Synopsys DW-HDMI specifics over to YAML schemas.

The original example and usage of clock-names uses a reversed "isfr"
and "iahb" clock-names, the rewritten YAML bindings uses the reversed
instead of fixing the device trees order.

The #sound-dai-cells optional property has been added to match this node
as a sound dai.

The port connection table has been dropped in favor of a description
of each port.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190808085522.21950-2-narmstrong@baylibre.com