nvme-tcp: don't check blk_mq_tag_to_rq when receiving pdu data

We already validate it when receiving the c2hdata pdu header
and this is not changing so this is a redundant check.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>