Adds support for Amlogic A1 USB Control Glue HW.

The Amlogic A1 SoC Family embeds 1 USB Controllers:
- a DWC3 IP configured as Host for USB2 and USB3

A glue connects the controllers to the USB2 PHY of A1 SoC.
Signed-off-by: Yue Wang <yue.wang@amlogic.com>
Signed-off-by: Hanjie Lin <hanjie.lin@amlogic.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>