From: Charl Liu <liuchang_125125@xxxxxxx>Errm.
The Bayhub's SD/MMC Card interface driver implements card detection,
card initialization, and other application level functions. The whole
project is divided into 9 patches to commit. Patch [1/9] and patch
[2/9] commit the Kconfig and Makefile, and the other code is divided
into 7 patches (patch [3/9] to patch [9/9]) by function.