usb: ohci: s3c2410: allow probing from device tree

Allows configuring Samsung's s3c2410 USB OHCI controller using a
devicetree.

Signed-off-by: Sergio Prado <sergio.prado@e-labworks.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>