RDMA/rtrs-srv: Avoid null pointer deref during path establishment

In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs-srv: Avoid null pointer deref during path establishment For RTRS path establishment, RTRS client initiates and completes con_num of connections. After establishing all its connections, the information is exchanged between the client and server through the info_req message. During this exchange, it is essential that all connections have been established, and the state of the RTRS srv path is CONNECTED. So add these sanity checks, to make sure we detect and abort process in error scenarios to avoid null pointer deref.