vhost: define VIRTIO_F_VERSION_1 if it is missing

Older kernel headers don't have the definition of this macro, so define
it if necessary.

This is the same workaround as used in rte_vhost/vhost.h.

Change-Id: I01e0661db05de517adf8e24a47c63d32853cd385
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>

lib/vhost/vhost.c

@@ -64,6 +64,11 @@ static char dev_dirname[PATH_MAX] = "";
 #define SPDK_CACHE_LINE_SIZE RTE_CACHE_LINE_SIZE
 
 #define MAX_VHOST_DEVICE	1024
+
+#ifndef VIRTIO_F_VERSION_1
+#define VIRTIO_F_VERSION_1 32
+#endif
+
 #define VHOST_USER_F_PROTOCOL_FEATURES	30
 
 /* Features supported by SPDK VHOST lib. */