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/broadcom/bcm_ep/board.c b/board/broadcom/bcm_ep/board.c
index 63fb98b..e4dbe42 100644
--- a/board/broadcom/bcm_ep/board.c
+++ b/board/broadcom/bcm_ep/board.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <cpu_func.h>
+#include <init.h>
 #include <asm/io.h>
 #include <config.h>
 #include <netdev.h>