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 <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Don Zickus <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/annotate.h

···
 	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];
 };