usb: renesas_usbhs: Add Renesas USBHS common code

Renesas SuperH has USBHS IP which can switch Host / Function.
This driver is designed so that Host / Function may dynamically change.
This patch add usb/renesas_usbhs and common code for SuperH USBHS.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>