common: Move RAM-sizing functions to init.h

These functions relate to memory init so move them into the init
header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-davinci/misc.c b/arch/arm/mach-davinci/misc.c
index 80e9642..3e51852 100644
--- a/arch/arm/mach-davinci/misc.c
+++ b/arch/arm/mach-davinci/misc.c
@@ -11,6 +11,7 @@
 #include <common.h>
 #include <env.h>
 #include <i2c.h>
+#include <init.h>
 #include <net.h>
 #include <asm/arch/hardware.h>
 #include <asm/io.h>