Add support for ram vectors to the ARMv7-M architecture

ChangeLog

arch/Kconfig

arch/arm/Kconfig

arch/arm/src/armv7-m/ram_vectors.h

arch/arm/src/armv7-m/up_ramvec_attach.c

arch/arm/src/armv7-m/up_ramvec_initialize.c

arch/arm/src/kinetis/Make.defs

arch/arm/src/kinetis/kinetis_irq.c

arch/arm/src/lm/Make.defs

arch/arm/src/lm/lm_irq.c

arch/arm/src/lpc17xx/Make.defs

arch/arm/src/lpc17xx/lpc17_irq.c

arch/arm/src/lpc43xx/Make.defs

arch/arm/src/lpc43xx/lpc43_irq.c

arch/arm/src/sam3u/Make.defs

arch/arm/src/sam3u/sam3u_irq.c

arch/arm/src/stm32/Make.defs

arch/arm/src/stm32/stm32_irq.c

configs/stm32f4discovery/ostest/defconfig

include/nuttx/arch.h