STM32:  Move STM32F42xxx SYSCFG definitions out of stm32f40xxx_syscfg.h into their own stm32f42xxx_syscfg.h header file

STM32:  Move STM32F42xxx RCC definitions out of stm32f40xxx_rcc.h into their own stm32f42xxx_rcc.h header file

STM32:  Move STM32F42xxx DMA definitions out of stm32f40xxx_dma.h into their own stm32f42xxx_dma.h header file

STM32:  Move STM32F42xxx pinmap definitions out of stm32f40xxx_pinmap.h into their own stm32f42xxx pinmap.h header file

samdl/sam_usb.h: fix USBDEV_CTRLB_SPDCONF defines Datasheet 03-2015 and 06-2015 is wrong. These defines are correct verified with analyser and also same values are used on Atmel xdk-asf-3.24.2 sources.  From Janne Rosberg.

More changes to LPC3450 pin configuration:  The hardware ETM pins will not toggle unless the SLEW FAST bit is set.  From  Alessandro Temil.

SAMD21: Last fix to header files caused a compile problem because logic used a value which is no longer available for the SAMD21

Add support for a BOARDIOC_RESET boardctl() command.  Enable configuration options to support BOARDIOC_RESET for ARMv6-M and ARMv7-M

Simulatin:  Save the intial terminal mode and restore this before terminating.  Otherwise, the NSH shutdown command leaves the console in raw mode

sim configuration: Add support for board_app_initialize() which is needed when CONFIG_LIB_BOARDCTL=y

Fix a Cortex-A compilation error in the vfork() logic when system calls are enabled in modes other than CONFIG_BUILD_KERNEL.

arch/arm/src/sama5/sam_ehci.c:  Fix some bad conditional compilation that left a function undefined if CONFIG_USBHOST_ASYNCH is not selected.