dt-bindings: mediatek: Replace Tinghan Shen in maintainers

dt-bindings: mediatek: Replace Tinghan Shen in maintainers

Emails to Tinghan Shen bounce permanently with "550 Relaying mail to
tinghan.shen@mediatek.com is not allowed (in reply to RCPT TO command)",
so switch to AngeloGioacchino Del Regno - Mediatek SoC platform
maintainer.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://patch.msgid.link/20260116172915.99811-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>