perf tools: Move tracing_path stuff under same namespace

perf tools: Move tracing_path stuff under same namespace

Renaming all functions touching tracing_path under same namespace. New
interface is:

  char tracing_path[];
  - tracing mount path

  char tracing_events_path[];
  - tracing mount/events path

  void tracing_path_set(const char *mountpoint);
  - setting directly tracing_path(_events), used by --debugfs-dir option

  const char *tracing_path_mount(void);
  - initial setup of tracing_(events)_path, called from perf.c
    mounts debugfs/tracefs if needed and possible

  char *get_tracing_file(const char *name);
  void put_tracing_file(char *file);
  - get/put tracing file path

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1441180605-24737-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>