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/board/technologic/ts4800/ts4800.c b/board/technologic/ts4800/ts4800.c
index 82eb0c2..ff1a189 100644
--- a/board/technologic/ts4800/ts4800.c
+++ b/board/technologic/ts4800/ts4800.c
@@ -7,6 +7,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/io.h>
 #include <asm/gpio.h>
 #include <asm/arch/imx-regs.h>