common: Drop init.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/freescale/mx6memcal/mx6memcal.c b/board/freescale/mx6memcal/mx6memcal.c
index d01127e..ea7a563 100644
--- a/board/freescale/mx6memcal/mx6memcal.c
+++ b/board/freescale/mx6memcal/mx6memcal.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/arch/sys_proto.h>
 
 DECLARE_GLOBAL_DATA_PTR;