Kinetis usb driver

First attempt at a usb device controller driver for kinetis. derived from pic32mx usb driver, which uses the same usb controller.

STM32: Fix typo

Just update duty if frequency is not changed and PSM started.  This removeis glitch or blinking when only duty is frequently changed.

lpc43 GPIO Interrupts enabled and fixed (not all cases tested)

STM32 TIM: Assure that a compilation error will occur if the old timer input clock frequency definitions are used

STM32 Timer: Generalize and extend calculation of per-timer pre-scaler value.  Inspired by original proposal from Pierre-noel Bouteville.

This reverts commit 082d3222.