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/inversepath/usbarmory/usbarmory.c b/board/inversepath/usbarmory/usbarmory.c
index e9eea40..4fa34e1 100644
--- a/board/inversepath/usbarmory/usbarmory.c
+++ b/board/inversepath/usbarmory/usbarmory.c
@@ -10,6 +10,7 @@
 #include <common.h>
 #include <command.h>
 #include <fs.h>
+#include <init.h>
 #include <asm/io.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/sys_proto.h>