drivers: regulator: add Maxim 8998 driver

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

This patch adds voltage regulator driver for Maxim 8998 chip. This chip
is used on Samsung Aquila and GONI boards and provides following
functionalities:
- 4 BUCK voltage converters, 17 LDO power regulators and 5 other power
  controllers
- battery charger

This patch adds basic driver for voltage regulators and MAX 8998 MFD core.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 6bf56c9..671b81a 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -100,6 +100,15 @@
 	help
 	  Say y here to support the voltage regulaltor of Maxim MAX8925 PMIC.
 
+config REGULATOR_MAX8998
+	tristate "Maxim 8998 voltage regulator"
+	depends on I2C
+	default n
+	help
+	  This driver controls a Maxim 8998 voltage output regulator
+	  via I2C bus. The provided regulator is suitable for S3C6410
+	  and S5PC1XX chips to control VCC_CORE and VCC_USIM voltages.
+
 config REGULATOR_TWL4030
 	bool "TI TWL4030/TWL5030/TWL6030/TPS695x0 PMIC"
 	depends on TWL4030_CORE