[PATCH 05/10] vfio: Use IOMMU_CAP_ENFORCE_CACHE_COHERENCY for vfio_file_enforced_coherent()

[Tian, Kevin]

> From: Jason Gunthorpe <jgg at nvidia.com>
> Sent: Tuesday, November 1, 2022 8:26 PM
> And this:
> 
> 	/*
> 	 * If the device does not have
> IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
> 	 * any domain later attached to it will also not support it. If the cap
> 	 * is set then the iommu_domain eventually attached to the
> device/group
> 	 * must must use a domain with enforce_cache_coherency().
> 	 */

duplicated 'must'