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/dhelectronics/dh_imx6/dh_imx6_spl.c b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
index f2c3ac3..fd6099c 100644
--- a/board/dhelectronics/dh_imx6/dh_imx6_spl.c
+++ b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/crm_regs.h>
 #include <asm/arch/imx-regs.h>