[PATCH v5 07/13] iommufd/selftest: Add container_of helpers

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Saturday, October 26, 2024 7:50 AM
> 
> Use these inline helpers to shorten those container_of lines.
> 
> Note that one of them goes back and forth between iommu_domain and
> mock_iommu_domain, which isn't necessary. So drop its container_of.
> 
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>