linkstation: fix warning: "CONFIG_IDENT_STRING" redefined

Commit 09c2e90 "unify version_string" defines a default value for
CONFIG_IDENT_STRING in version.h, so any private settings musty be
done before including this file.  Move the include for version.h after
the one for common.h to fix the build problem.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
diff --git a/board/linkstation/linkstation.c b/board/linkstation/linkstation.c
index e564e50..7640856 100644
--- a/board/linkstation/linkstation.c
+++ b/board/linkstation/linkstation.c
@@ -21,8 +21,8 @@
  * MA 02111-1307 USA
  */
 
-#include <version.h>
 #include <common.h>
+#include <version.h>
 #include <mpc824x.h>
 #include <asm/io.h>
 #include <ns16550.h>