usb: dwc2: Add reset control to dwc2

Allow for platforms that have a reset controller driver in place to bring
the USB IP out of reset.

Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>