ARM: OMAP: get rid of OMAP_TAG_USB, v2

OMAP_TAGS should vanish soon since they're not generic arm tags.
Most of them can be converted to a platform_data or parsed
from a command line like e.g. serial tag.

For OMAP_TAG_USB we just let boards call omap_usb_init()
passing a pointer to omap_usb_config.

Patch updated by Tony for mainline, basically make
n770 and h4 compile. Also folded in a fix for OSK
by David Brownell <dbrownell@users.sourceforge.net>.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>