vhost: rcu annotation fixup

When built with rcu checks enabled, vhost triggers
bogus warnings as vhost features are read without
dev->mutex sometimes, and private pointer is read
with our kind of rcu where work serves as a
read side critical section.

Fixing it properly is not trivial.
Disable the warnings by stubbing out the checks for now.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.h

@@ -173,9 +173,9 @@ static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 {
 	unsigned acked_features;
 
-	acked_features =
-		rcu_dereference_index_check(dev->acked_features,
-					    lockdep_is_held(&dev->mutex));
+	/* TODO: check that we are running from vhost_worker or dev mutex is
+	 * held? */
+	acked_features = rcu_dereference_index_check(dev->acked_features, 1);
 	return acked_features & (1 << bit);
 }