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/variscite/dart_6ul/dart_6ul.c b/board/variscite/dart_6ul/dart_6ul.c
index 0f00506..a4f449d 100644
--- a/board/variscite/dart_6ul/dart_6ul.c
+++ b/board/variscite/dart_6ul/dart_6ul.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2019 Parthiban Nallathambi <parthitce@gmail.com>
  */
 
+#include <init.h>
 #include <net.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/crm_regs.h>