usb: dwc3: Add MSM dwc3 wrapper

Add MSM USB3.0 super-speed controller.
The MSM USB3.0 controller is a wrapper of Synopsys's DesignWare
USB3.0 controller which also includes other HW units as the DBM.

The copper device-tree now includes a new device for this controller,
which will be attached to the dwc3-msm.c driver.
The dwc3-msm.c driver will be used for MSM specific operations of USB3.0
(as managing the DBM) and for now it just add in runtime a core dwc3 device
that will be attached to the dwc3/core.c driver.

Change-Id: I1e0a9144971b2de533d4d1ce7ac5f0c3584d1930
Signed-off-by: Amit Blay <ablay@codeaurora.org>
Signed-off-by: Ido Shayevitz <idos@codeaurora.org>