perf annotate: Move nr_events from annotate_browser to annotation struct

Paving the way to move more stuff out of TUI and into the generic
annotation library.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.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-8vqax6wgfqohelot8j8zsfvs@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/annotate.h

@@ -165,6 +165,7 @@ struct annotation {
 	pthread_mutex_t		lock;
 	u64			max_coverage;
 	struct annotation_line	**offsets;
+	int			nr_events;
 	bool			have_cycles;
 	struct annotated_source *src;
 };