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/toradex/verdin-imx8mm/spl.c b/board/toradex/verdin-imx8mm/spl.c
index c614fc7a..338952e 100644
--- a/board/toradex/verdin-imx8mm/spl.c
+++ b/board/toradex/verdin-imx8mm/spl.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <image.h>
+#include <init.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/ddr.h>
 #include <asm/arch/imx8mm_pins.h>