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/nokia/rx51/rx51.c b/board/nokia/rx51/rx51.c
index a282fe6..60a2e36 100644
--- a/board/nokia/rx51/rx51.c
+++ b/board/nokia/rx51/rx51.c
@@ -23,6 +23,7 @@
 
 #include <common.h>
 #include <env.h>
+#include <init.h>
 #include <watchdog.h>
 #include <malloc.h>
 #include <twl4030.h>