It is broken since Xen 4.9 [1] and it will not build in Xen 4.12. Also,
it is not built by default since QEMU 2.6.

[1] https://lists.xenproject.org/archives/html/xen-devel/2018-09/msg00313.html



Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>