smb3: add dynamic tracepoints for flush and close

smb3: add dynamic tracepoints for flush and close

We only had dynamic tracepoints on errors in flush
and close, but may be helpful to trace enter
and non-error exits for those.  Sample trace examples
(excerpts) from "cp" and "dd" show two of the new
tracepoints.

  cp-22823 [002] .... 123439.179701: smb3_enter: _cifsFileInfo_put: xid=10
  cp-22823 [002] .... 123439.179705: smb3_close_enter: xid=10 sid=0x98871327 tid=0xfcd585ff fid=0xc7f84682
  cp-22823 [002] .... 123439.179711: smb3_cmd_enter: sid=0x98871327 tid=0xfcd585ff cmd=6 mid=43
  cp-22823 [002] .... 123439.180175: smb3_cmd_done: sid=0x98871327 tid=0xfcd585ff cmd=6 mid=43
  cp-22823 [002] .... 123439.180179: smb3_close_done: xid=10 sid=0x98871327 tid=0xfcd585ff fid=0xc7f84682

  dd-22981 [003] .... 123696.946011: smb3_flush_enter: xid=24 sid=0x98871327 tid=0xfcd585ff fid=0x1917736f
  dd-22981 [003] .... 123696.946013: smb3_cmd_enter: sid=0x98871327 tid=0xfcd585ff cmd=7 mid=123
  dd-22981 [003] .... 123696.956639: smb3_cmd_done: sid=0x98871327 tid=0x0 cmd=7 mid=123
  dd-22981 [003] .... 123696.956644: smb3_flush_done: xid=24 sid=0x98871327 tid=0xfcd585ff fid=0x1917736f

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>