xfs: xfs_trace.c: remove duplicated #include

Remove duplicated #include('s) in
  fs/xfs/linux-2.6/xfs_trace.c

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

fs/xfs/linux-2.6/xfs_trace.c

@@ -50,7 +50,6 @@
 #include "quota/xfs_dquot_item.h"
 #include "quota/xfs_dquot.h"
 #include "xfs_log_recover.h"
-#include "xfs_buf_item.h"
 #include "xfs_inode_item.h"
 
 /*