dt-bindings: usb: dwc3-imx8mp: add imx8mp dwc3 glue bindings

NXP imx8mp integrates 2 dwc3 3.30b IP and add some wakeup logic
to support low power mode, the glue layer is for this wakeup
functionality, which has a separated interrupt, can support
wakeup from U3 and connect events for host, and vbus wakeup for
device.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Li Jun <jun.li@nxp.com>
Link: https://lore.kernel.org/r/1609241866-9508-2-git-send-email-jun.li@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>