perf hist: In init, ensure mem_info is put on error paths

perf hist: In init, ensure mem_info is put on error paths

Rather than exit the internal map_symbols directly, put the mem-info
that does this and also lowers the reference count on the mem-info
itself otherwise the mem-info is being leaked.

Fixes: 56e144fe98260a0f ("perf mem_info: Add and use map_symbol__exit and addr_map_symbol__exit")
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>