dt-bindings: display: imx: add binding for i.MX8MP HDMI TX

dt-bindings: display: imx: add binding for i.MX8MP HDMI TX

The HDMI TX controller on the i.MX8MP SoC is a Synopsys designware IP
core with a little bit of SoC integration around it.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20240203165307.7806-10-aford173@gmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240203165307.7806-10-aford173@gmail.com