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/synopsys/nsim/nsim.c b/board/synopsys/nsim/nsim.c
index f384f70..00e5cc3 100644
--- a/board/synopsys/nsim/nsim.c
+++ b/board/synopsys/nsim/nsim.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <dm/device.h>
 #include <virtio_types.h>
 #include <virtio.h>