mfd: Add subdevs in max8925

Add subdevs in MAX8925. MAX8925 includes regulator, backlight and touch
components.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index ee416ee..d63ab2e 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -197,6 +197,7 @@
 config MFD_MAX8925
 	tristate "Maxim Semiconductor MAX8925 PMIC Support"
 	depends on I2C
+	select MFD_CORE
 	help
 	  Say yes here to support for Maxim Semiconductor MAX8925. This is
 	  a Power Management IC. This driver provies common support for