Add stm32f429 discovery configs.
Copied from asm/memory.h (dummy) to workaround
arm-none-eabi-ld:arch/arm/kernel/vmlinux.lds:364: syntax error
Merge from https://github.com/robutest/uclinux.git
      commit 7149dc935d286a77e6266772ae7bd36cc8a0ca44

Author: Tayfun Karan <tmk@robutest.com>

STM32F429I-DISCOVERY board support added.
  Virtual frame buffer driver enabled. The framebuffer Can be accessed via "/dev/fb0".
  uCLinux RomFS support patched. RomFS image address can be entered from config file.
  Kernel XIP (eXecute In Place) support enabled. Data segment copy functions added.
  RomFS image XIP support added. Working on SDRAM or ROM can be selected from config file.