perf hists: Rename hists__inc_stats()

The existing hists__inc_nr_entries() is a misnomer as it's not only
increasing ->nr_entries but also other stats.  So rename it to more
general hists__inc_stats().

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1398327843-31845-3-git-send-email-namhyung@kernel.org


Signed-off-by: Jiri Olsa <jolsa@kernel.org>