sun6i: Add dram initialization code

Add full support for dram initialization, using a fixed clock and autodetection
of the memory organization (numbers of channels, bus-width, etc.).

This is based on dram_sun6i.c and dram.h from u-boot in the Allwinner A31 SDK,
extended with extra initialization sequences and the autodetect algorithm
from boot0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/arch/arm/cpu/armv7/sunxi/Makefile b/arch/arm/cpu/armv7/sunxi/Makefile
index 48cca0b..3b6ae47 100644
--- a/arch/arm/cpu/armv7/sunxi/Makefile
+++ b/arch/arm/cpu/armv7/sunxi/Makefile
@@ -30,6 +30,7 @@
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_MACH_SUN4I)	+= dram_sun4i.o
 obj-$(CONFIG_MACH_SUN5I)	+= dram_sun4i.o
+obj-$(CONFIG_MACH_SUN6I)	+= dram_sun6i.o
 obj-$(CONFIG_MACH_SUN7I)	+= dram_sun4i.o
 ifdef CONFIG_SPL_FEL
 obj-y	+= start.o