perf tools: Fix pthread_attr_setaffinity_np build error

Feature detection for pthread_attr_setaffinity_np was failing, producing
this error:

  In file included from bench/futex-hash.c:17:0:
  bench/futex.h:73:19: error: conflicting types for ‘pthread_attr_setaffinity_np’
   static inline int pthread_attr_setaffinity_np(pthread_attr_t *attr,
                   ^
  In file included from bench/futex.h:72:0,
                   from bench/futex-hash.c:17:
  /usr/include/pthread.h:407:12: note: previous declaration of ‘pthread_attr_setaffinity_np’ was here
   extern int pthread_attr_setaffinity_np (pthread_attr_t *__attr,
            ^
  make[3]: *** [bench/futex-hash.o] Error 1
  make[2]: *** [bench] Error 2
  make[2]: *** Waiting for unfinished jobs....

  This was because compiling test-pthread-attr-setaffinity-np.c
  failed due to the function arguments:

  test-pthread-attr-setaffinity-np.c: In function ‘main’:
  test-pthread-attr-setaffinity-np.c:11:2: warning: null argument where non-null required (argument 3) [-Wnonnull]
    ret = pthread_attr_setaffinity_np(&thread_attr, 0, NULL);
    ^
  So fix the arguments.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1424774766-24194-1-git-send-email-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>