iommu/dma: avoid expensive indirect calls for sync operations
When IOMMU is on, the actual synchronization happens in the same cases
as with the direct DMA. Advertise %DMA_F_CAN_SKIP_SYNC in IOMMU DMA to
skip sync ops calls (indirect) for non-SWIOTLB buffers.
iavf yields +10% of Mpps on Rx. This also unblocks batched allocations
of XSk buffers when IOMMU is active.
Co-developed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>