bios_emulator: Correct ordering of includes

We should include common.h before other includes. This actually causes
a build error on chromebook_link.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/bios_emulator/bios.c b/drivers/bios_emulator/bios.c
index 152d70a..dd4c0a4 100644
--- a/drivers/bios_emulator/bios.c
+++ b/drivers/bios_emulator/bios.c
@@ -42,8 +42,8 @@
 ****************************************************************************/
 
 #define __io
-#include <asm/io.h>
 #include <common.h>
+#include <asm/io.h>
 #include "biosemui.h"
 
 /*----------------------------- Implementation ----------------------------*/