nvme-pci: clear the prp2 field when not used

stable inclusion
from stable-v5.10.160
commit 74b139c63f0775cf79266e9d9546c62b73fb3385
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7PZZC
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=74b139c63f0775cf79266e9d9546c62b73fb3385



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[ Upstream commit a56ea614 ]

If the prp2 field is not filled in nvme_setup_prp_simple(), the prp2
field is garbage data. According to nvme spec, the prp2 is reserved if
the data transfer does not cross a memory page boundary, so clear it to
zero if it is not used.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yong Hu <yong.hu@windriver.com>