msm: rpm-regulator: Add stubs for rpm_vreg_set_*() APIs on copper

Copper platform clock and acpuclock drivers need to call the
rpm_vreg_set_vdd() API to set vdd_dig and vdd_mem voltages. Until a
full rpm-regulator driver for copper is available, add stub functions
that always return success.

To do this a new MSM_RPM_REGULATOR Kconfig is added.

Change-Id: I0e7c3ab7cd56f7760f0083f4aaac000fdb56d0ec
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
diff --git a/arch/arm/mach-msm/Kconfig b/arch/arm/mach-msm/Kconfig
index 182c15f..c049b5f 100644
--- a/arch/arm/mach-msm/Kconfig
+++ b/arch/arm/mach-msm/Kconfig
@@ -75,6 +75,7 @@
 	select ARCH_REQUIRE_GPIOLIB
 	select MSM_ADM3
 	select REGULATOR
+	select MSM_RPM_REGULATOR
 	select MSM_V2_TLMM
 	select MSM_PIL
 	select MSM_SCM
@@ -128,6 +129,7 @@
 	select MSM_SCM if SMP
 	select MSM_DIRECT_SCLK_ACCESS
 	select REGULATOR
+	select MSM_RPM_REGULATOR
 	select MSM_RPM
 	select MSM_XO
 	select MSM_QDSP6_APR
@@ -230,6 +232,9 @@
 	select MSM_RPM
 	select MSM_SPM_V2
 	select MSM_NATIVE_RESTART
+	select REGULATOR
+	select MSM_RPM_REGULATOR
+
 endmenu
 
 choice
@@ -1572,6 +1577,14 @@
 	  for idle power collapse, wait the number of microseconds in case
 	  Modem becomes ready soon.
 
+config MSM_RPM_REGULATOR
+	bool "RPM regulator driver"
+	depends on RPM && REGULATOR
+	help
+	  Compile in support for the RPM regulator driver, used for setting
+	  voltages and other parameters of the various power rails supplied
+	  by some Qualcomm PMICs.
+
 config MSM_PIL
 	bool "Peripheral image loading"
 	select FW_LOADER