regulator: max8973: add regulator driver support

The MAXIM MAX8973 high-efficiency, three phase, DC-DC step-down
switching regulator delievers up to 9A of output current. Each
phase operates at a 2MHz fixed frequency with a 120 deg shift
from the adjacent phase, allowing the use of small magnetic
component.

Add regulator driver for this device.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 67d47b59..2b80312 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -204,6 +204,16 @@
 	  via I2C bus. Maxim 8952 has one voltage output and supports 4 DVS
 	  modes ranging from 0.77V to 1.40V by 0.01V steps.
 
+config REGULATOR_MAX8973
+	tristate "Maxim MAX8973 voltage regulator "
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  The MAXIM MAX8973 high-efficiency. three phase, DC-DC step-down
+	  switching regulator delievers up to 9A of output current. Each
+	  phase operates at a 2MHz fixed frequency with a 120 deg shift
+	  from the adjacent phase, allowing the use of small magnetic component.
+
 config REGULATOR_MAX8997
 	tristate "Maxim 8997/8966 regulator"
 	depends on MFD_MAX8997