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/Makefile b/drivers/regulator/Makefile
index e431eed..3b51e0d 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -34,6 +34,7 @@
 obj-$(CONFIG_REGULATOR_MAX8907) += max8907-regulator.o
 obj-$(CONFIG_REGULATOR_MAX8925) += max8925-regulator.o
 obj-$(CONFIG_REGULATOR_MAX8952) += max8952.o
+obj-$(CONFIG_REGULATOR_MAX8973) += max8973-regulator.o
 obj-$(CONFIG_REGULATOR_MAX8997) += max8997.o
 obj-$(CONFIG_REGULATOR_MAX8998) += max8998.o
 obj-$(CONFIG_REGULATOR_MAX77686) += max77686.o