mmc: Kconfig: downgrade CONFIG_MMC_DEBUG for host drivers only

We have removed all code depending on CONFIG_MMC_DEBUG
from mmc core now. So it's safe to make CONFIG_MMC_DEBUG
just for host drivers only and we expect to kill this option
in the future.

Signed-off-by: Shawn Lin <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/Kconfig

···
 	  If you want MMC/SD/SDIO support, you should say Y here and
 	  also to your specific host controller driver.
 
-config MMC_DEBUG
-	bool "MMC debugging"
-	depends on MMC != n
-	help
-	  This is an option for use by developers; most people should
-	  say N here.  This enables MMC core and driver debugging.
-
 if MMC
 
 source "drivers/mmc/core/Kconfig"

drivers/mmc/Makefile

···
 # Makefile for the kernel mmc device drivers.
 #
 
-subdir-ccflags-$(CONFIG_MMC_DEBUG) := -DDEBUG
-
 obj-$(CONFIG_MMC)		+= core/
 obj-$(subst m,y,$(CONFIG_MMC))	+= host/

drivers/mmc/host/Kconfig

···
 
 comment "MMC/SD/SDIO Host Controller Drivers"
 
+config MMC_DEBUG
+	bool "MMC host drivers debugginG"
+	depends on MMC != n
+	help
+	  This is an option for use by developers; most people should
+	  say N here. This enables MMC host driver debugging. And further
+	  added host drivers please don't invent their private macro for
+	  debugging.
+
 config MMC_ARMMMCI
 	tristate "ARM AMBA Multimedia Card Interface support"
 	depends on ARM_AMBA