SDMMC: how to use gpio-interrupt to detect card rather than to use register-interrupt.

SDMMC: how to use gpio-interrupt to detect card rather than to use register-interrupt.
 If your project is synchronized with the server after 2012-9-27, you can modify your board-xxx.c lock like the board-rk30-sdk.c int the commit.
Of course, if your project is such older, you have to cherry-pick the bellow commit
            commit 9ab32ee1a15f01f251022bb20dcdb2f1729c7fd3
Author: xbw <xbw@rock-chips.com>
Date:   Thu Sep 27 21:23:07 2012 +0800

    SDMMC:use gpio-interrupt to detect card.
    Please attention to define the detect-pin name and the insert-card voltage in your board_xxxx.c.

M       arch/arm/mach-rk2928/board-rk2928-a720.c
M       arch/arm/plat-rk/include/plat/board.h
M       drivers/mmc/host/Kconfig
M       drivers/mmc/host/rk29_sdmmc.c