MIPS: JZ4740: Probe OHCI platform device via DT

MIPS: JZ4740: Probe OHCI platform device via DT

The DT fragment will select the ohci-platform driver, since that can
handle the JZ4740 OHCI just fine. While I don't have a JZ4740-based
board with anything connected to the USB host controller, I did test
the generic OHCI driver successfully on a JZ4770-based board.

The device is disabled by default; boards that want to use it can
override the "status" property. The mass-production Qi LB60 boards
don't use the USB host controller.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13104/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>