vhost: fix missing header includes

vhost: fix missing header includes

The vhost header files were missing definitions from headers to allow
them to be compiled up individually.

Fixes: d7280c9fffcb ("vhost: support selective datapath")
Fixes: a49f758d1170 ("vhost: split vDPA header file")
Fixes: 939066d96563 ("vhost/crypto: add public function implementation")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>