dt-bindings: usb: mtk-xhci: add wakeup interrupt

Add an interrupt which is EINT usually to support runtime PM,
meanwhile add "interrupt-names" property, for backward
compatibility, it's optional and used when wakeup interrupt
exists
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1618031406-15347-2-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml

@@ -46,7 +46,18 @@ properties:
       - const: ippc  # optional, only needed for case 1.
 
   interrupts:
-    maxItems: 1
+    description:
+      use "interrupts-extended" when the interrupts are connected to the
+      separate interrupt controllers
+    minItems: 1
+    items:
+      - description: xHCI host controller interrupt
+      - description: optional, wakeup interrupt used to support runtime PM
+
+  interrupt-names:
+    items:
+      - const: host
+      - const: wakeup
 
   power-domains:
     description: A phandle to USB power domain node to control USB's MTCMOS