iommu: Tidy domain for iommu_setup_dma_ops()

iommu: Tidy domain for iommu_setup_dma_ops()

This function can only be called on the default_domain. Trivally pass it
in. In all three existing cases, the default domain was just attached to
the device.

This avoids iommu_setup_dma_ops() calling iommu_get_domain_for_dev() that
will be used by external callers.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>