board_f: Make init_helpers generic

This header file is used by two archs. It could be used by all of them
since it allows the cache to be on during relocation. Move it into a
generic file.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/board_f.c b/common/board_f.c
index bafe3aa..f928c3d 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -18,6 +18,7 @@
 #include <fs.h>
 #include <i2c.h>
 #include <initcall.h>
+#include <init_helpers.h>
 #include <logbuff.h>
 #include <malloc.h>
 #include <mapmem.h>
@@ -46,9 +47,6 @@
 #include <watchdog.h>
 #include <asm/io.h>
 #include <asm/sections.h>
-#if defined(CONFIG_X86) || defined(CONFIG_ARC)
-#include <asm/init_helpers.h>
-#endif
 #if defined(CONFIG_X86) || defined(CONFIG_ARC) || defined(CONFIG_XTENSA)
 #include <asm/relocate.h>
 #endif