CIFS: Improve readdir verbosity

commit dcd87838c06f05ab7650b249ebf0d5b57ae63e1e upstream.

Downgrade the loglevel for SMB2 to prevent filling the log
with messages if e.g. readdir was interrupted. Also make SMB2
and SMB1 codepaths do the same logging during readdir.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>