arm: Include asm/setup.h explictly

Include this header where needed so we do not need to rely on common.h.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/Synology/ds109/ds109.c b/board/Synology/ds109/ds109.c
index b46c09d..0c2f525 100644
--- a/board/Synology/ds109/ds109.c
+++ b/board/Synology/ds109/ds109.c
@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <miiphy.h>
+#include <asm/setup.h>
 #include <asm/arch/cpu.h>
 #include <asm/arch/soc.h>
 #include <asm/arch/mpp.h>