dt-bindings: mfd: syscon: Add mt8365-syscfg

Document Mediatek mt8365-syscfg

Signed-off-by: Bernhard Rosenkränzer <bero@baylibre.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230125143503.1015424-4-bero@baylibre.com