mmc: replace CONFIG_GENERIC_MMC with CONFIG_MMC

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>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index f51ae2c..0d56f10 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -374,7 +374,7 @@
 
 config SPL_MMC_SUPPORT
 	bool "Support MMC"
-	depends on SPL && GENERIC_MMC
+	depends on SPL && MMC
 	help
 	  Enable support for MMC (Multimedia Card) within SPL. This enables
 	  the MMC protocol implementation and allows any enabled drivers to