regulator: new drivers for AD5398 and AD5821

The AD5398 and AD5821 are single 10-bit DAC with 120 mA output current
sink capability. They feature an internal reference and operates from
a single 2.7 V to 5.5 V supply.

This driver supports both the AD5398 and the AD5821.  It adapts into the
voltage and current framework.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 4e7feec..c256668 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -8,6 +8,7 @@
 obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o
 obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o
 
+obj-$(CONFIG_REGULATOR_AD5398) += ad5398.o
 obj-$(CONFIG_REGULATOR_BQ24022) += bq24022.o
 obj-$(CONFIG_REGULATOR_DUMMY) += dummy.o
 obj-$(CONFIG_REGULATOR_LP3971) += lp3971.o