tqma6: fix typo in header guard define

Signed-off-by: Markus Niebel <Markus.Niebel@tq-group.com>

board/tqc/tqma6/tqma6_bb.h

@@ -6,7 +6,7 @@
  */
 
 #ifndef __TQMA6_BB__
-#define __TQMA6_BB
+#define __TQMA6_BB__
 
 #include <common.h>