ARM: SAMSUNG: Add support for Power Domain control

This patch implements Power Domain control based on Runtime PM framework.
Each Power Domain is represented by a Power Domain device and the devices
belong to these Power Domains should be set as a child device of the Power
Domain devices. The corresponding drivers of the devices should implement
Runtime PM to control the Power Domains.

Signed-off-by: Changhwan Youn <chaos.youn at samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/plat-samsung/Kconfig b/arch/arm/plat-samsung/Kconfig
index dcd6eff..2ebf415 100644
--- a/arch/arm/plat-samsung/Kconfig
+++ b/arch/arm/plat-samsung/Kconfig
@@ -333,4 +333,12 @@
 	  and above. This code allows a set of interrupt to wakeup-mask
 	  mappings. See <plat/wakeup-mask.h>
 
+comment "Power Domain"
+
+config SAMSUNG_PD
+	bool "Samsung Power Domain"
+	depends on PM_RUNTIME
+	help
+	  Say Y here if you want to control Power Domain by Runtime PM.
+
 endif