usb: dwc3: Introduce OTG driver for dwc3

This is first release of otg driver for the dwc3 Synopsys USB3 core.
The otg driver implements the otg final state machine and control the
activation of the device controller or host controller.

In this first implementation, only simple DRD mode is implemented,
determine if A or B device according to the ID pin as reflected in the
OSTS.ConIDSts field.

Change-Id: I6533490aa2adfe3641ffa926666867c19a979217
Signed-off-by: Ido Shayevitz <idos@codeaurora.org>