osd: update osd_stat_updated field if we force to report to monitor

osd: update osd_stat_updated field if we force to report to monitor

On tick_without_osd_lock() waking up, we will force an immediate
report to monitor if a long enough period has elapsed since our
last report was sent.

However, the send_pg_stats() procedure is a noop unless either
osd_stat_updated field is set or pg_stat_queue is empty.
Since the latter condition is non-deterministic, we shall
manually set osd_stat_updated here to kick a pg relevant report
off.

Signed-off-by: xie xingguo <xie.xingguo@zte.com.cn>