RT-Thread/rt-thread — pull request #324 by yuht (2014-08-27 01:48:37+00:00)
Title: rt_sdcard_control(),relace and add

1. replace global variable "SDCfg" with "dev->user_data"
2. add case RT_DEVICE_CTRL_BLK_SYNC and RT_DEVICE_CTRL_BLK_ERASE.