perf hists browser: Cleanup callchain print functions

perf hists browser: Cleanup callchain print functions

The hist_browser__show_callchain() and friends don't need to be that
complex.  They're splitted in 3 pieces - one for traversing top-level
tree, other one for special casing first chains in the top-level
entries, and last one for recursive traversing inner trees.  It led to
code duplication and unnecessary complexity IMHO.

Simplify the function and consolidate the logic into a single function
- it can recursively call itself.  A little difference in printing
  callchains in top-level tree can be handled with a small change.

It should have no functional change.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1408583746-5540-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>