SAM PIO: sam_pio.h needs to include chip/sam_memorymap.h in order to resolve some conditional logic properly

Added missing EXTI definitions for the STM32 F3; Correct an error the port D base address in the STM32 F3 and F37 memory maps.  From Greg Meiste.

STM32F4-Discovery: Part of logic to initialize the ELF loaded in the board startup logic.  From Leo aloe3132

binfmt: Fix a debug statement that does not have the correct number of arguments.  From Leo aloe3132

EFM32 USB host: Add missing trace data and some missing connection-related logic; update a configuration

STM32F429i-Disco: Add some missing USB host configureation.  Fix some some duplicate class registration that causes infinite loops in USB registry searches

USB hub:  Add a configuration option to fallback to polling mode if the the HCD async method does not work.  Don't call DRVR_CANCEL twice, and certainly not from the interrupt level.  Add so checks so that we do not do some normal asynchronous actions if the hub has been disconnected

STM32F4-Discovery: Add configuration option to select the size of the stack used with the usbhost waiter.  Needs to be bigger when a hub is supported

USB HUB: Fix a deadlock that can occur if the HCD and the HUB try to share the high priority work queue.  Now how work must be done on the low priority work queue.

USB HUB: Update all USB host connection waiter application threads to use the the new connection interface