There is a plan to build the kernel with -Wimplicit-fallthrough and
these places in the code produced warnings (W=1).
This commit removes the following warnings:
drivers/mmc/host/jz4740_mmc.c:745:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/mmc/host/jz4740_mmc.c:779:3: warning: this statement may fall through [-Wimplicit-fallthrough=]