perf annotate browser: Do not pass nr_events in disasm_rb_tree__insert

perf annotate browser: Do not pass nr_events in disasm_rb_tree__insert

We now keep samples_nr in struct annotation_line, so there's no need to
pass nr_events to disasm_rb_tree__insert function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171011150158.11895-27-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>