perf sort: Align cpu column to right

perf sort: Align cpu column to right

Since cpu number is a natural number, it'd be more appropriate
aligning it to right.

Before:

  # Overhead  CPU      Command:  Pid          Shared Object
  # ........  ...  .................  .....................
  #
       8.91%  8    gnome-shell: 1497  perf-1497.map
       8.90%  7    gnome-shell: 1497  perf-1497.map
       8.86%  9    gnome-shell: 1497  perf-1497.map
       8.83%  6    gnome-shell: 1497  perf-1497.map
       8.81%  10   gnome-shell: 1497  perf-1497.map
       7.44%  5    gnome-shell: 1497  perf-1497.map
       6.20%  3    gnome-shell: 1497  perf-1497.map
       5.10%  0    gnome-shell: 1497  perf-1497.map

After:

  # Overhead  CPU      Command:  Pid          Shared Object
  # ........  ...  .................  .....................
  #
       8.91%    8  gnome-shell: 1497  perf-1497.map
       8.90%    7  gnome-shell: 1497  perf-1497.map
       8.86%    9  gnome-shell: 1497  perf-1497.map
       8.83%    6  gnome-shell: 1497  perf-1497.map
       8.81%   10  gnome-shell: 1497  perf-1497.map
       7.44%    5  gnome-shell: 1497  perf-1497.map
       6.20%    3  gnome-shell: 1497  perf-1497.map
       5.10%    0  gnome-shell: 1497  perf-1497.map

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1356599507-14226-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>