virtio: remove virtio_tswap16s() call in vring_packed_event_read()

Commit d152cdd ("virtio: use virtio accessor to access packed event")
switched using of address_space_read_cached() to virito_lduw_phys_cached()
to access packed descriptor event.

When we used address_space_read_cached(), we needed to call
virtio_tswap16s() to handle the endianess of the field, but
virito_lduw_phys_cached() already handles it internally, so we no longer
need to call virtio_tswap16s() (as the commit had done for `off_wrap`,
but forgot for `flags`).

Fixes: d152cdd ("virtio: use virtio accessor to access packed event")
Cc: [email protected]
Cc: [email protected]
Reported-by: Xoykie <[email protected]>
Link: https://lore.kernel.org/qemu-devel/CAFU8RB_pjr77zMLsM0Unf9xPNxfr_--Tjr49F_eX32ZBc5o2zQ@mail.gmail.com
Signed-off-by: Stefano Garzarella <[email protected]>
Message-Id: <[email protected]>
Acked-by: Jason Wang <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Reviewed-by: Eugenio Pérez <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

Author: stefano-garzarella

hw/virtio/virtio.c

@@ -323,7 +323,6 @@ static void vring_packed_event_read(VirtIODevice *vdev,
     /* Make sure flags is seen before off_wrap */
     smp_rmb();
     e->off_wrap = virtio_lduw_phys_cached(vdev, cache, off_off);
-    virtio_tswap16s(vdev, &e->flags);
 }
 
 static void vring_packed_off_wrap_write(VirtIODevice *vdev,