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/arch/sandbox/cpu/start.c b/arch/sandbox/cpu/start.c
index b6ff5c3..c6a2bbe 100644
--- a/arch/sandbox/cpu/start.c
+++ b/arch/sandbox/cpu/start.c
@@ -6,6 +6,7 @@
 #include <common.h>
 #include <command.h>
 #include <errno.h>
+#include <init.h>
 #include <os.h>
 #include <cli.h>
 #include <sort.h>