DEBUG: iommu: Sanity-check of page requests

maillist inclusion
category: feature
bugzilla: 51855
CVE: NA

Reference: https://jpbrucker.net/git/linux/commit/?h=sva/2021-03-01&id=b81eda9426104cf59867c1ccf6b147fc0727e08b



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A bunch of sanity-checks. For development only, because it probably adds
a large overhead to the fast path. The fault only comes from the IOMMU
driver, which is obviously bug-free so this won't ever trigger.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Lijun Fang <fanglijun3@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>