Now CONFIG_GENERIC_MMC and CONFIG_MMC match for all defconfig.
We do not need two options for the same feature. Deprecate the
former.
This commit was generated with the sed script 's/GENERIC_MMC/MMC/'
and manual fixup of drivers/mmc/Kconfig.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>