ksmbd: smbd: fix connection dropped issue

When there are bursty connection requests,
RDMA connection event handler is deferred and
Negotiation requests are received even if
connection status is NEW.

To handle it, set the status to CONNECTED
if Negotiation requests are received.

Reported-by: Yufan Chen <wiz.chen@gmail.com>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Tested-by: Yufan Chen <wiz.chen@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>