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/sifive/fu540/fu540.c b/board/sifive/fu540/fu540.c
index 47a2090..e9d1cf9 100644
--- a/board/sifive/fu540/fu540.c
+++ b/board/sifive/fu540/fu540.c
@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <init.h>
 #include <linux/delay.h>
 #include <linux/io.h>