dt-bindings: timer: mtk-timer: add support for MT8516

Add binding documentation of mtk-timer for MT8516 SoC.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
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

@@ -17,6 +17,7 @@ Required properties:
 	* "mediatek,mt8127-timer" for MT8127 compatible timers (GPT)
 	* "mediatek,mt8135-timer" for MT8135 compatible timers (GPT)
 	* "mediatek,mt8173-timer" for MT8173 compatible timers (GPT)
+	* "mediatek,mt8516-timer" for MT8516 compatible timers (GPT)
 	* "mediatek,mt6577-timer" for MT6577 and all above compatible timers (GPT)
 
 	For those SoCs that use SYST