U-Boot 移植：暂存代码

编译通过，先把代码保存。代码状态如下：

du@ubuntu:~/u-boot$ git status -uno
On branch chunrollboard
Your branch is up-to-date with 'origin/chunrollboard'.

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   arch/arm/Kconfig
        modified:   arch/arm/Makefile
        modified:   arch/arm/include/asm/global_data.h
        modified:   drivers/gpio/Makefile
        modified:   drivers/mmc/Makefile
        modified:   drivers/mtd/nand/Makefile
        modified:   drivers/serial/Makefile
        modified:   drivers/spi/Makefile
        modified:   drivers/usb/host/Makefile

no changes added to commit (use "git add" and/or "git commit -a")