dt-bindings: usb: mtk-xhci: remove redefinitions of usb3-lpm-capable

The property usb3-lpm-capable is defined in usb-xhci.yaml which is
already referenced in this file, so no need 'description' and 'type'
anymore.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1617181553-3503-2-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -100,9 +100,7 @@ properties:
   vbus-supply:
     description: Regulator of USB VBUS5v
 
-  usb3-lpm-capable:
-    description: supports USB3.0 LPM
-    type: boolean
+  usb3-lpm-capable: true
 
   usb2-lpm-disable: true