USB: omap_udc build fixes (sync with linux-omap)

Resync the omap_udc driver with the latest from the Linux-OMAP tree.
Changes include DMA API updates (it builds again!), clock/pm updates,
minor bugfixes, whitespace.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>