virtio: fix vring_align() on 64-bit windows

virtio: fix vring_align() on 64-bit windows

long is 32-bits on 64-bit windows, which caused the top half of the
address to be truncated; this patch changes it to use the
QEMU_ALIGN_UP macro which does not suffer the same problem

Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>