Previously, both map and remap trigger rnbd_clt_set_dev_attr to set
some members in rnbd_clt_dev such as wc, fua and logical_block_size
etc, but those members are only useful for map scenario given the
setup_request_queue is only called from the path:

rnbd_clt_map_device -> rnbd_client_setup_device

Since rnbd_clt_map_device frees rsp after rnbd_client_setup_device,
we can pass rsp to rnbd_client_setup_device and it's callees, which
means queue's attributes can be set directly from relevant members
of rsp instead from rnbd_clt_dev.

After that, we can kill 11 members from rnbd_clt_dev, and we don't
need rnbd_clt_set_dev_attr either.
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Link: https://lore.kernel.org/r/20220706133152.12058-5-guoqing.jiang@linux.devSigned-off-by: Jens Axboe <axboe@kernel.dk>