net/virtio: fix duplicate naming of include guard
net/virtio: fix duplicate naming of include guard

"The macro name '_VHOST_NET_USER_H' of this include guard is used
in 2 different header files."

lib/librte_vhost/vhost_user.h has the same include guard.
Renamed the include guard in vhost.h to differentiate.

Fixes: 6a84c37e3975 ("net/virtio-user: add vhost-user adapter layer")
Cc: stable@dpdk.org

Signed-off-by: Andrius Sirvys <9fda2fb7a487e4ba252282165ee50070574f1f0a@intel.com>
Acked-by: Rami Rosen <d906574dd7f018d5d95e7b7a8107cdf708745f05@gmail.com>
Reviewed-by: Tiwei Bie <f338cf29d7d69ff1bc99f755ebfb0eb0accd409e@intel.com>

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