nvme-pci: allocate nvme_command within driver pdu

stable inclusion
from stable-v5.10.127
commit 938f594266a671b7cc90bf96d2bee27f9e4f3339
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5XDDK

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=938f594266a671b7cc90bf96d2bee27f9e4f3339



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[ Upstream commit af7fae85 ]

Except for pci, all the nvme transport drivers allocate a command within
the driver's pdu. Align pci with everyone else by allocating the nvme
command within pci's pdu and replace the .queue_rq() stack variable with
this.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>