dt-bindings: soc: add i.MX93 mediamix blk ctrl

Add DT bindings for i.MX93 MEDIAMIX BLK CTRL.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>