This allows the driver the receive the mm and always a device during
allocation. Later patches need this to properly setup the notifier when
the domain is first allocated.

Remove ops->domain_alloc() as SVA was the only remaining purpose.
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1-v9-5cd718286059+79186-smmuv3_newapi_p2b_jgg@nvidia.comSigned-off-by: Will Deacon <will@kernel.org>