smb3: display session id in debug data

Displaying the session id in /proc/fs/cifs/DebugData
is needed in order to correlate Linux client information
with network and server traces for many common support
scenarios.  Turned out to be very important for debugging.

Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>