smb3: display bytes_read and bytes_written in smb3 stats

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>

fs/cifs/smb2ops.c

@@ -950,6 +950,9 @@ smb2_print_stats(struct seq_file *m, struct cifs_tcon *tcon)
 	 *  Can't display SMB2_NEGOTIATE, SESSION_SETUP, LOGOFF, CANCEL and ECHO
 	 *  totals (requests sent) since those SMBs are per-session not per tcon
 	 */
+	seq_printf(m, "\nBytes read: %llu  Bytes written: %llu",
+		   (long long)(tcon->bytes_read),
+		   (long long)(tcon->bytes_written));
 	seq_printf(m, "\nTreeConnects: %d total %d failed",
 		   atomic_read(&sent[SMB2_TREE_CONNECT_HE]),
 		   atomic_read(&failed[SMB2_TREE_CONNECT_HE]));