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>

drivers/ddr/altera/sdram_s10.c

@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <div64.h>
 #include <fdtdec.h>
+#include <init.h>
 #include <ram.h>
 #include <reset.h>
 #include "sdram_s10.h"