perf annotate: Replace symbol__alloc_hists() with symbol__hists()

Its a bit shorter, so ditch the old symbol__alloc_hists() function.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-m7tienxk7dijh5ln62yln1m9@git.kernel.org


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