RDMA/hns: Bugfix for SCC hem free

The method of hem free for SCC context is different from qp context.

In the current version, if free SCC hem during the execution of qp free,
there may be smmu error as below:

 arm-smmu-v3 arm-smmu-v3.1.auto: event 0x10 received:
 arm-smmu-v3 arm-smmu-v3.1.auto:  0x00007d0000000010
 arm-smmu-v3 arm-smmu-v3.1.auto:  0x000012000000017c
 arm-smmu-v3 arm-smmu-v3.1.auto:  0x00000000000009e0
 arm-smmu-v3 arm-smmu-v3.1.auto:  0x0000000000000000

As SCC context is still used by hardware after qp free, we can solve this
problem by removing SCC hem free from hns_roce_qp_free.

Fixes: 6a157f7d ("RDMA/hns: Add SCC context allocation support for hip08")
Signed-off-by: Yangyang Li <liyangyang20@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>