Support for the STM32F429 from Ken Pettit

ChangeLog

arch/arm/include/stm32/chip.h

arch/arm/include/stm32/stm32f40xxx_irq.h

arch/arm/src/stm32/Kconfig

arch/arm/src/stm32/chip/stm32_flash.h

arch/arm/src/stm32/chip/stm32_i2c.h

arch/arm/src/stm32/chip/stm32_pwr.h

arch/arm/src/stm32/chip/stm32f40xxx_dma.h

arch/arm/src/stm32/chip/stm32f40xxx_pinmap.h

arch/arm/src/stm32/chip/stm32f40xxx_rcc.h

arch/arm/src/stm32/chip/stm32f40xxx_syscfg.h

arch/arm/src/stm32/chip/stm32f40xxx_vectors.h

arch/arm/src/stm32/stm32_allocateheap.c

arch/arm/src/stm32/stm32_fsmc.h

arch/arm/src/stm32/stm32f40xxx_rcc.c