We were only displaying bytes_read and bytes_written in cifs
stats, fix smb3 stats to also display them.  Sample output
with this patch:

    cat /proc/fs/cifs/Stats:

CIFS Session: 1
Share (unique mount targets): 2
SMB Request/Response Buffer: 1 Pool size: 5
SMB Small Req/Resp Buffer: 1 Pool size: 30
Operations (MIDs): 0

0 session 0 share reconnects
Total vfs operations: 94 maximum at one time: 2

1) \\localhost\test
SMBs: 214
Bytes read: 502092  Bytes written: 31457286
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
Creates: 52 total 3 failed
Closes: 48 total 0 failed
Flushes: 0 total 0 failed
Reads: 17 total 0 failed
Writes: 31 total 0 failed
...
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>