iommufd: Remove unnecessary IOMMU_DEV_FEAT_IOPF

The iopf enablement has been moved to the iommu drivers. It is unnecessary
for iommufd to handle iopf enablement. Remove the iopf enablement logic to
avoid duplication.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://lore.kernel.org/r/20250418080130.1844424-8-baolu.lu@linux.intel.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>