perf hists: Reset width of output fields with header length

perf hists: Reset width of output fields with header length

Some fields missed to set default column length so it broke align in
--stdio output.  Add perf_hpp__reset_width() to set it to a sane
default value.

Note that this change will ignore -w/--column-widths option for now.

Before:
  $ perf report -F cpu,comm,overhead --stdio
  ...
  # CPU          Command  Overhead
  #   ...............  ........
  #
    0          firefox     2.65%
    0      kworker/0:0     1.45%
    0          swapper     5.52%
    0         synergys     0.92%
    1          firefox     4.54%

After:
  # CPU          Command  Overhead
  # ...  ...............  ........
  #
      0          firefox     2.65%
      0      kworker/0:0     1.45%
      0          swapper     5.52%
      0         synergys     0.92%
      1          firefox     4.54%

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1400480762-22852-17-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>