iommu: Add iommu_paging_domain_alloc() interface

iommu: Add iommu_paging_domain_alloc() interface

Commit <17de3f5fdd35> ("iommu: Retire bus ops") removes iommu ops from
bus. The iommu subsystem no longer relies on bus for operations. So the
bus parameter in iommu_domain_alloc() is no longer relevant.

Add a new interface named iommu_paging_domain_alloc(), which explicitly
indicates the allocation of a paging domain for DMA managed by a kernel
driver. The new interface takes a device pointer as its parameter, that
better aligns with the current iommu subsystem.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20240610085555.88197-2-baolu.lu@linux.intel.com
Signed-off-by: Will Deacon <will@kernel.org>