perf copyfile: Move copyfile routines to separate files

Further reducing the util.c hodgepodge files.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-0i62zh7ok25znibyebgq0qs4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/build-id.c

@@ -7,12 +7,13 @@
  * Copyright (C) 2009, 2010 Red Hat Inc.
  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
  */
-#include "util.h" // copyfile_ns(), lsdir(), mkdir_p(), rm_rf()
+#include "util.h" // lsdir(), mkdir_p(), rm_rf()
 #include <dirent.h>
 #include <errno.h>
 #include <stdio.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include "util/copyfile.h"
 #include "dso.h"
 #include "build-id.h"
 #include "event.h"