RDMA/core: Fix unsafe linked list traversal after failing to allocate CQ

It's not safe to access the next CQ in list_for_each_entry() after
invoking ib_free_cq(), because the CQ has already been freed in current
iteration.  It should be replaced by list_for_each_entry_safe().

Fixes: c7ff819a ("RDMA/core: Introduce shared CQ pool API")
Link: https://lore.kernel.org/r/1598963935-32335-1-git-send-email-liweihang@huawei.com


Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>