dt-bindings: mtk-sysirq: Add compatible for Mediatek MT8183

This adds dt-binding documentation of SYSIRQ for Mediatek MT8183 SoC
Platform.

Signed-off-by: Erin Lo <erin.lo@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>