Revert "swiotlb-xen: pass dev_addr to swiotlb_tbl_unmap_single"

commit dbdd74763f1faf799fbb9ed30423182e92919378 upstream.

This reverts commit 2c3fc8d26dd09b9d7069687eead849ee81c78e46.

This commit broke on x86 PV because entries in the generic SWIOTLB are
indexed using (pseudo-)physical address not DMA address and these are
not the same in a x86 PV guest.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>