perf tools: Remove string.h, unistd.h and sys/stat.h from util.h

Not needed in this header, added to the places that need FILE,
putchar(), access() and a few other prototypes.

Link: http://lkml.kernel.org/n/tip-xxtdsl6nsna82j7puwbdjqhs@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 685653f..d679389 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -15,7 +15,10 @@
  *
  */
 #include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <sys/uio.h>
+#include <unistd.h>
 #include "util.h"
 #include "event.h"
 #include "strlist.h"