iommufd: Avoid duplicated __iommu_group_set_core_domain() call

iommufd: Avoid duplicated __iommu_group_set_core_domain() call

For the fault-capable hwpts, the iommufd_hwpt_detach_device() calls both
iommufd_fault_domain_detach_dev() and iommu_detach_group(). This would have
duplicated __iommu_group_set_core_domain() call since both functions call
it in the end. This looks no harm as the __iommu_group_set_core_domain()
returns if the new domain equals to the existing one. But it makes sense to
avoid such duplicated calls in caller side.

Link: https://patch.msgid.link/r/20240908114256.979518-2-yi.l.liu@intel.com
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>