virtio-scsi: use virtio wrappers to access headers

virtio-scsi: use virtio wrappers to access headers

Note that st*_raw and ld*_raw are effectively replaced by st*_p and ld*_p.

Signed-off-by: Rusty Russell <[email protected]>
Reviewed-by: Anthony Liguori <[email protected]>
[ pass VirtIODevice * to memory accessors,
  converted new tswap locations to virtio_tswap,
  Greg Kurz <[email protected]> ]
Signed-off-by: Greg Kurz <[email protected]>
Reviewed-by: Alexander Graf <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>