perf bench numa: Make sure dprintf() is not defined

When building with clang we get this error:

  bench/numa.c:46:9: error: 'dprintf' macro redefined [-Werror,-Wmacro-redefined]
  #define dprintf(x...) do { if (g && g->p.show_details >= 1) printf(x); } while (0)
          ^
  /usr/include/bits/stdio2.h:145:12: note: previous definition is here
  #   define dprintf(fd, ...) \
             ^
    CC       /tmp/build/perf/tests/parse-no-sample-id-all.o
  1 error generated.

So, make sure it is undefined before using that name.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Jakub Jelen <jjelen@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-f654o2svtrutamvxt7igwz74@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bench/numa.c

@@ -43,6 +43,7 @@
 /*
  * Debug printf:
  */
+#undef dprintf
 #define dprintf(x...) do { if (g && g->p.show_details >= 1) printf(x); } while (0)
 
 struct thread_data {