usb: dwc2: force to host mode if not support HNP/SRP

In current code, after running the command of "usb start", the controller
will keep in otg mode and can't switch to host mode if not support
SNP/SRP capability. So add the property of "hnp-srp-disable" in the DTS
to config the contrller work in force mode of host.

Signed-off-by: Meng Dongyang <daniel.meng@rock-chips.com>