IB/srpt: Fix srpt_cm_req_recv() error path (2/2)

If a login request was received through the RDMA/CM and if an error occurs
during login, clear rdma_cm_id->context instead of ib_cm_id->context.

Fixes: 63cf1a90 ("IB/srpt: Add RDMA/CM support")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>