dt-bindings: mediatek: update bindings for MT8183 systimer

This commit adds mt8183 compatible node in mtk-timer binding document.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dehui Sun <dehui.sun@mediatek.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/timer/mediatek,mtk-timer.txt

@@ -21,6 +21,7 @@ Required properties:
 	* "mediatek,mt6577-timer" for MT6577 and all above compatible timers (GPT)
 
 	For those SoCs that use SYST
+	* "mediatek,mt8183-timer" for MT8183 compatible timers (SYST)
 	* "mediatek,mt7629-timer" for MT7629 compatible timers (SYST)
 	* "mediatek,mt6765-timer" for MT6765 and all above compatible timers (SYST)