sunxi: add support for the DDR2 in V3s SoC

Allwinner V3s SoC features a co-packaged DDR2 DRAM chip, which needs its
timing param.

Add support for it.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 3e52947..1df24cf 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -220,6 +220,9 @@
 config SUNXI_DRAM_DDR3
 	bool
 
+config SUNXI_DRAM_DDR2
+	bool
+
 choice
 	prompt "DRAM Type and Timing"
 	default SUNXI_DRAM_DDR3_1333
@@ -231,6 +234,13 @@
 	This option is the original only supported memory type, which suits
 	many H3/H5/A64 boards available now.
 
+config SUNXI_DRAM_DDR2_V3S
+	bool "DDR2 found in V3s chip"
+	select SUNXI_DRAM_DDR2
+	---help---
+	This option is only for the DDR2 memory chip which is co-packaged in
+	Allwinner V3s SoC.
+
 endchoice
 endif