mfd: Add AAT2870 mfd driver

Add mfd core driver for AnalogicTech AAT2870.
The AAT2870 is communication through I2C and contains backlight and
regulator components.

Signed-off-by: Jin Park <jinyoungp@nvidia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index c261364..21574bd 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -760,6 +760,16 @@
 config TPS65911_COMPARATOR
 	tristate
 
+config MFD_AAT2870_CORE
+	bool "Support for the AnalogicTech AAT2870"
+	select MFD_CORE
+	depends on I2C=y && GPIOLIB
+	help
+	  If you say yes here you get support for the AAT2870.
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the
+	  functionality of the device.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"