iommu/vt-d: Check if SVA is supported when attaching the SVA domain

iommu/vt-d: Check if SVA is supported when attaching the SVA domain

Attach of a SVA domain should fail if SVA is not supported, move the check
for SVA support out of IOMMU_DEV_FEAT_SVA and into attach.

Also check when allocating a SVA domain to match other drivers.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://lore.kernel.org/r/20250228092631.3425464-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>