USB device driver of Topcliff PCH

This patch adds the USB device driver of EG20T(Topcliff) PCH.

EG20T PCH is the platform controller hub that is going to be used in
Intel's upcoming general embedded platform. All IO peripherals in
EG20T PCH are actually devices sitting on AMBA bus.
EG20T PCH has USB device I/F. Using this I/F, it is able to access system
devices connected to USB device.

Signed-off-by: Toshiharu Okada <toshiharu-linux@dsn.okisemi.com>
Acked-by: Michał Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>