net/smc: remove redundant dma sync ops

mainline inclusion
from mainline-v6.0-rc1
commit 6d52e2de
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I77IM8
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/smc?id=6d52e2de6415b7a035b3e8dc4ccffd0da25bbfb9



--------------------------------

smc_ib_sync_sg_for_cpu/device are the ops used for dma memory cache
consistency. Smc sndbufs are dma buffers, where CPU writes data to
it and PCIE device reads data from it. So for sndbufs,
smc_ib_sync_sg_for_device is needed and smc_ib_sync_sg_for_cpu is
redundant as PCIE device will not write the buffers. Smc rmbs
are dma buffers, where PCIE device write data to it and CPU read
data from it. So for rmbs, smc_ib_sync_sg_for_cpu is needed and
smc_ib_sync_sg_for_device is redundant as CPU will not write the buffers.

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Litao Jiao <jiaolitao@sangfor.com.cn>