perf annotate: Fix sizeof_sym_hist overflow issue

The annotated_source::sizeof_sym_hist could easily overflow int size,
resulting in crash in __symbol__inc_addr_samples.

Changing its type int size_t as was probably intended from beginning
based on the initialization code in symbol__alloc_hist.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444068369-20978-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/annotate.h

@@ -122,7 +122,7 @@ struct annotated_source {
 	struct list_head   source;
 	struct source_line *lines;
 	int    		   nr_histograms;
-	int    		   sizeof_sym_hist;
+	size_t		   sizeof_sym_hist;
 	struct cyc_hist	   *cycles_hist;
 	struct sym_hist	   histograms[0];
 };