Please update your board-xxx-sdmmc.c in your old project.

Please update your board-xxx-sdmmc.c in your old project.
For exmaple board-rk30-sdk-sdmmc.c.

If you do not modify your files,you will encounter an error similar to the following.
      3066 4.2 develop-3.0的分支编译出错，报告
   drivers/built-in.o: In function rk29_sdmmc_set_ios
   bt_plat_smdk.c:(.text+0x16cfd8): undefined reference to rk29_sdmmc_gpio_open
   make: *** [.tmp_vmlinux1] 错误 1