vfio/iommu_type1: Fix the logic of updating num_non_hwdbm_domains

virt inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4WK5B


CVE: NA

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When a newly created iommu_domain is not HWDBM capable, the vfio_iommu's
num_non_hwdbm_domains field should increase but failed to increase. This
fixes this bug.

Fixes: d2373c56 (vfio/iommu_type1: Add HWDBM status maintenance)
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Tested-by: Kunkun Jiang <jiangkunkun@huawei.com>
Reviewed-by: Kunkun Jiang <jiangkunkun@huawei.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>