ARM: dts: Add STM32429i-EVAL board support

Main features of STM32429i-EVAL evaluation kit are:
 - STM32F429 Cortex-M4 MCU @180MHz
   * 2MB internal Flash
   * 256KB internal RAM
 - 32MB SDRAM
 - 16MB NOR Flash
 - 2MB SRAM
 - 4.3" TFT LCD with resistive touchscreen
 - SDCard connector (SDIO compatible)
 - 1x USB 2.0 OTG + 1x USB 1.1 OTG
 - Ethernet

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>