RDMA/hns: Fix type of sq_signal_bits

This bit should be in type of enum ib_sig_type, or there will be a sparse
warning.

Fixes: bfe86035 ("RDMA/hns: Fix cast from or to restricted __le32 for driver")
Link: https://lore.kernel.org/r/1612517974-31867-3-git-send-email-liweihang@huawei.com


Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>