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/colibri_t20/colibri_t20.c b/board/toradex/colibri_t20/colibri_t20.c
index e0b27e9..6cecbe5 100644
--- a/board/toradex/colibri_t20/colibri_t20.c
+++ b/board/toradex/colibri_t20/colibri_t20.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/funcmux.h>
 #include <asm/arch/pinmux.h>