ARM: socfpga: support suspend to ram

Add code that requests that the sdr controller go into
self-refresh mode.  This code is run from ocram.

Suspend-to-RAM and EDAC support are mutually exclusive on
SOCFPGA.  If the EDAC is enabled, it will prevent the
platform from going into suspend.

Example of how to request to suspend to ram:
 $ echo enabled > \
/sys/devices/soc/ffc02000.serial0/tty/ttyS0/power/wakeup

 $ echo -n mem > /sys/power/state

Signed-off-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
index f420a1b..90efdeb 100644
--- a/arch/arm/mach-socfpga/Kconfig
+++ b/arch/arm/mach-socfpga/Kconfig
@@ -1,4 +1,4 @@
-config ARCH_SOCFPGA
+menuconfig ARCH_SOCFPGA
 	bool "Altera SOCFPGA family" if ARCH_MULTI_V7
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select ARM_AMBA
@@ -9,3 +9,11 @@
 	select HAVE_ARM_SCU
 	select HAVE_ARM_TWD if SMP
 	select MFD_SYSCON
+
+if ARCH_SOCFPGA
+config SOCFPGA_SUSPEND
+	bool "Suspend to RAM on SOCFPGA"
+	help
+	  Select this if you want to enable Suspend-to-RAM on SOCFPGA
+	  platforms.
+endif