smb: client/smbdirect: introduce SMBDIRECT_SOCKET_ERROR

smb: client/smbdirect: introduce SMBDIRECT_SOCKET_ERROR

This will be used to turn SMBDIRECT_SOCKET_CONNECTED into an
error within smbd_disconnect_rdma_connection() on the client
and smb_direct_disconnect_rdma_connection() on the server.

We do this in a single commit with the client as otherwise it
won't build because the enum value is not handled in the
switch statement.

Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>