osd: Add op_process_latency in perf counter

@liewegas, @yuyuyu101

Original pull requests: https://github.com/ceph/ceph/pull/1096, https://github.com/ceph/ceph/pull/1108, https://github.com/ceph/ceph/pull/1118

Fixes: #7167

Signed-off-by: Ray Lv <xiangyulv@gmail.com>