smb: server: fix leak of active_num_conn in ksmbd_tcp_new_connection()

smb: server: fix leak of active_num_conn in ksmbd_tcp_new_connection()

On kthread_run() failure in ksmbd_tcp_new_connection(), the transport is
freed via free_transport(), which does not decrement active_num_conn,
leaking this counter.

Replace free_transport() with ksmbd_tcp_disconnect().

Fixes: 0d0d4680db22e ("ksmbd: add max connections parameter")
Cc: stable@vger.kernel.org
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>