iommu/vt-d: Delete dev_has_feat callback

The commit 262948f8 ("iommu: Delete iommu_dev_has_feature()") has
deleted the iommu_dev_has_feature() interface. Remove the dev_has_feat
callback to avoid dead code.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210929072030.1330225-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20211014053839.727419-7-baolu.lu@linux.intel.com


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