perf hists browser: Cleanup hist_browser__update_percent_limit()

perf hists browser: Cleanup hist_browser__update_percent_limit()

The previous patch introduced __rb_hierarchy_next() function with
various move direction like HMD_FORCE_CHILD but missed to change using
it some place.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1456488800-28124-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>