In general, dma_alloc_coherent() returns a CPU virtual address and
a DMA address, and we have no guarantee that the underlying memory
even has an associated struct page at all.

This patch gets rid of the page operation after dma_alloc_coherent,
and records the VA returned form dma_alloc_coherent in the struct
of hem in hns RoCE driver.

Fixes: 9a443537("IB/hns: Add driver files for hns RoCE driver")
Signed-off-by: NWei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: NShaobo Xu <xushaobo2@huawei.com>
Signed-off-by: NLijun Ou <oulijun@huawei.com>
Signed-off-by: NYixian Liu <liuyixian@huawei.com>
Signed-off-by: NXiping Zhang (Francis) <zhangxiping3@huawei.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>