vhost: fix build with old kernels
vhost: fix build with old kernels

This patch fixes compile failure with old kernels which have no
VIRTIO_F_ANY_LAYOUT defined.

Fixes: 5a8bb6e9020f ("vhost: claim to support any layout feature")

Signed-off-by: Zhihong Wang <efad9c89b3a8db7900a2572fdee08ebbff3cfc6b@intel.com>
Reviewed-by: Maxime Coquelin <9a2667dee3b90866bbc9c2696cff2b7d5616c95a@redhat.com>
Tested-by: Jerin Jacob <5bca7d2a432bc0f5422b70b2701a4e4fa32edd00@caviumnetworks.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk