RDMA/hns: Remove unused MTT functions

The MTT (Memory Translate Table) interface is no longer used to configure
the buffer address to BT (Base Address Table) that requires driver
mapping.  Because the MTT is not compatible with multi-hop addressing of
the hip08, it is replaced by MTR (Memory Translate Region) interface, and
all the MTT functions should be removed.

Link: https://lore.kernel.org/r/1588071823-40200-3-git-send-email-liweihang@huawei.com


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