smb: server: only turn into SMBDIRECT_SOCKET_CONNECTED when negotiation is done

smb: server: only turn into SMBDIRECT_SOCKET_CONNECTED when negotiation is done

From SMBDIRECT_SOCKET_CREATED we now go via the following
stages:

1. SMBDIRECT_SOCKET_RDMA_CONNECT_NEEDED
   This indicated rdma_accept needs to be called

2. SMBDIRECT_SOCKET_RDMA_CONNECT_RUNNING
   This waits for RDMA_CM_EVENT_ESTABLISHED to
   arrive

3. SMBDIRECT_SOCKET_NEGOTIATE_NEEDED
   This waits for the negotiate request to
   arrive

4. SMBDIRECT_SOCKET_NEGOTIATE_RUNNING
   This indicates the negotiate request
   arrived and needs to be processed

5. SMBDIRECT_SOCKET_CONNECTED
   The connection is ready to use

This avoids the extra 'bool negotiation_requested'
and makes the steps more clear.

In future we may want to add trace points when
changing the states, which would be useful for
debugging.

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