perf hists browser: Consolidate callchain print functions in TUI

perf hists browser: Consolidate callchain print functions in TUI

Currently there're two callchain print functions in TUI - one for the
hists browser and another for file dump.  They do almost same job so
it'd be better consolidate the codes.

To do that, provide two callbacks to the generic logic - one for
printing and another for checking whether it should stop.

Signed-off-by: Namhyung Kim <namhyung@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/1408666401-594-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>