nvme-tcp: don't access released socket during error recovery

In the Linux kernel, the following vulnerability has been resolved:

nvme-tcp: don't access released socket during error recovery

While the error recovery work is temporarily failing reconnect attempts, running the 'nvme list' command causes a kernel NULL pointer dereference by calling getsockname() with a released socket.

During error recovery work, the nvme tcp socket is released and a new one created, so it is not safe to access the socket without proper check.