iommu: Move the iommu driver sysfs setup into iommu_init/deinit_device()

It makes logical sense that once the driver is attached to the device the
sysfs links appear, even if we haven't fully created the group_device or
attached the device to a domain.

Fix the missing error handling on sysfs creation since
iommu_init_device() can trivially handle this.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v3-328044aa278c+45e49-iommu_probe_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>