perf report: Left align dynamic entries in hierarchy

The dynamic entries are right-aligned unlike other entries since it
usually has numeric value.  But for the hierarchy mode, left alignment
is more appropriate IMHO.  Also trim spaces on the left so that we can
easily identify the hierarchy.

Before:

  $ perf report --hierarchy -i perf.data.kmem -s gfp_flags,ptr,bytes_req --stdio -g none
  ...
  #
  #       Overhead                                        gfp_flags /                ptr /          bytes_req
  # ..............  .................................................................................................
  #
      91.67%                   GFP_ATOMIC|GFP_NOWARN|GFP_NOMEMALLOC
         37.50%        0xffff8803f7669400
            37.50%                       448
          8.33%        0xffff8803f766be00
             8.33%                        96
          4.17%        0xffff8800d156dc00
             4.17%                       704

After:

  #       Overhead  gfp_flags / ptr / bytes_req
  # ..............  ....................................
  #
      91.67%        GFP_ATOMIC|GFP_NOWARN|GFP_NOMEMALLOC
         37.50%        0xffff8803f7669400
            37.50%        448
          8.33%        0xffff8803f766be00
             8.33%        96
          4.17%        0xffff8800d156dc00
             4.17%        704

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1456512767-1164-3-git-send-email-namhyung@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>