fix: add log to hint to set NCCL_IB_HCA env when _get_my_rdma_device raise an assertion failure

[specture724]

Please set 'NCCL_IB_HCA' or 'PS_P2P_STORE_RDMA_DEVICES' environment variable to choose proper number of RDMA devices. The number of RDMA devices should be less than or equal to GPU count, and GPU count should be divisible by the number of RDMA devices. The acceptable value by NCCL_IB_HCA is documented in 'https://docs.nvidia.com/deeplearning/nccl/user-guide/docs/env.html#id8'."