[PATCH] x86_64: implement dma_sync_single_range_for_{cpu,device}

Re-implement dma_sync_single_range_for_{cpu,device} for x86_64 using
swiotlb_sync_single_range_for_{cpu,device}.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>