usb: musb-new: omap2430: Enable DM_USB and OF support

With upcoming changes that require CONFIG_BLK, this broke
USB Mass Storage on the OMAP3 boards because if CONFIG_BLK is
enabled, it assumes that DM_USB is enabled, but it wasn't yet
available on omap3 and omap4 boards.

This patch converts the OMAP2430 MUSB glue to support DM_USB and
extracts the necessary information based on the device tree.

It's based on the ti-musb driver, but there are enough significant
differences in both the architecture and device tree entires between
am33xx and OMAP3/OMAP4, that I think it makes sense to continue to
keep the separate.

Per doc/driver-model/usb-info.txt, the USB gadget stuff hasn't
migrated to DM_USB yet, so this only supports USB Host for now.

Users wanting USB Gadgets will need to disable DM_USB and leave
it the old way for now.

Signed-off-by: Adam Ford <aford173@gmail.com>