regulator: pm8018-regulator: Add regulator driver for PM8018

Create a regulator driver to control all regulators on the Qualcomm
PM8018 PMIC chip.  This chip contains several different types of
regulators with a wide range of abilities and voltage ranges.

Five different regulator types are available on the PM8018.

PLDO     - PMOS low drop out linear regulator
NLDO     - NMOS low drop out linear regulator
NLDO1200 - 1.2A NMOS LDO (different control structure than other LDOs)
SMPS     - switched-mode power supply
VS       - voltage switch

The driver interfaces with the PMIC using Qualcomm's SSBI bus.
Calls to this bus are abstracted through the pm8xxx_readb/writeb API.

Signed-off-by: David Collins <collinsd@codeaurora.org>
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 1dfaa3c..4e5fd66 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -48,5 +48,6 @@
 obj-$(CONFIG_REGULATOR_PM8921) += pm8921-regulator.o
 obj-$(CONFIG_REGULATOR_GPIO) += gpio-regulator.o
 obj-$(CONFIG_REGULATOR_PM8058_XO) += pm8058-xo.o
+obj-$(CONFIG_REGULATOR_PM8018) += pm8018-regulator.o
 
 ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG