scsi: core: Refine how we set tag_set NUMA node

scsi: core: Refine how we set tag_set NUMA node

For SCSI hosts which enable host_tagset the NUMA node returned from
blk_mq_hw_queue_to_node() is NUMA_NO_NODE always. Then, since in
scsi_mq_setup_tags() the default we choose for the tag_set NUMA node is
NUMA_NO_NODE, we always evaluate the NUMA node as NUMA_NO_NODE in functions
like blk_mq_alloc_rq_map().

The reason we get NUMA_NO_NODE from blk_mq_hw_queue_to_node() is that the
hctx_idx passed is BLK_MQ_NO_HCTX_IDX - so we can't match against a (HW)
queue mapping index.

Improve this by defaulting the tag_set NUMA node to the same NUMA node of
the SCSI host DMA dev.

Link: https://lore.kernel.org/r/1648640315-21419-1-git-send-email-john.garry@huawei.com
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>