ARM: LPC32xx: USB Support

This patch adds OHCI support to the LPC32xx ARM platform. Besides the trivial
addition of platform "usb-ohci" support, fixes for the USB PLL have been added
to arch/arm/mach-lpc32xx/clock.c, ported from NXP's lpclinux.com.

(This is the mach-lpc32xx specific part, the USB subsystem specific changes are
in a separate patch for the USB maintainers.)

Signed-off-by: Roland Stigge <stigge@antcom.de>