Update U-Boot's build timestamp on every compile

Use the GNU 'date' command to auto-generate a new U-Boot
timestamp on every compile.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/trab/trab_fkt.c b/board/trab/trab_fkt.c
index 7273ef9..93b9490 100644
--- a/board/trab/trab_fkt.c
+++ b/board/trab/trab_fkt.c
@@ -25,6 +25,7 @@
 
 #include <common.h>
 #include <exports.h>
+#include <timestamp.h>
 #include <s3c2400.h>
 #include "tsc2000.h"
 #include "rs485.h"
@@ -296,7 +297,7 @@
 int do_info (void)
 {
 	printf ("Stand-alone application for TRAB board function test\n");
-	printf ("Built: %s at %s\n", __DATE__ , __TIME__ );
+	printf ("Built: %s at %s\n", U_BOOT_DATE, U_BOOT_TIME);
 
 	return 0;
 }