Define RDMA_DRIVER_ERDMA in enum rdma_driver_id.

Link: https://lore.kernel.org/r/20220727014927.76564-2-chengyou@linux.alibaba.comSigned-off-by: Cheng Xu <chengyou@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>