dt-bindings: soc: update the binding document for SCPSYS on MediaTek MT7622 SoC

Update the binding document for enabling SCPSYS on MediaTek MT7622 SoC.
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Signed-off-by: NChen Zhong <chen.zhong@mediatek.com>
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NMatthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/soc/mediatek/scpsys.txt

@@ -12,11 +12,13 @@ power/power_domain.txt. It provides the power domains defined in
 - include/dt-bindings/power/mt8173-power.h
 - include/dt-bindings/power/mt6797-power.h
 - include/dt-bindings/power/mt2701-power.h
+- include/dt-bindings/power/mt7622-power.h
 
 Required properties:
 - compatible: Should be one of:
 	- "mediatek,mt2701-scpsys"
 	- "mediatek,mt6797-scpsys"
+	- "mediatek,mt7622-scpsys"
 	- "mediatek,mt8173-scpsys"
 - #power-domain-cells: Must be 1
 - reg: Address range of the SCPSYS unit
@@ -26,6 +28,7 @@ Required properties:
                       enabled before enabling certain power domains.
 	Required clocks for MT2701: "mm", "mfg", "ethif"
 	Required clocks for MT6797: "mm", "mfg", "vdec"
+	Required clocks for MT7622: "hif_sel"
 	Required clocks for MT8173: "mm", "mfg", "venc", "venc_lt"
 
 Optional properties: