iommu/vt-d: Move clflush'es from iotlb_sync_map() to map_pages()

iommu/vt-d: Move clflush'es from iotlb_sync_map() to map_pages()

As the Intel VT-d driver has switched to use the iommu_ops.map_pages()
callback, multiple pages of the same size will be mapped in a call.
There's no need to put the clflush'es in iotlb_sync_map() callback.
Move them back into __domain_mapping() to simplify the code.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210720020615.4144323-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>