mmc: make optional the support for eMMC hardware partitioning

Not all boards have an eMMC and not all users have a need for this.
Allow to compile it out. By default it is still included.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 2fcdadd..d196eed 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -51,6 +51,13 @@
 	  are enabled by default, other may require additionnal flags or are
 	  enabled by the host driver.
 
+config MMC_HW_PARTITIONING
+	bool "Support for HW partitioning command(eMMC)"
+	default y
+	help
+	  This adds a command and an API to do hardware partitioning on eMMC
+	  devices.
+
 config MMC_IO_VOLTAGE
 	bool "Support IO voltage configuration"
 	help