Fix terrain not rendering when outside the world height

Yet another logic error. Pesky.

src/main/java/me/jellysquid/mods/sodium/client/render/chunk/occlusion/OcclusionCuller.java

@@ -293,7 +293,7 @@ private void initOutsideWorldHeight(WriteQueue<RenderSection> queue,
     private void tryVisitNode(WriteQueue<RenderSection> queue, int x, int y, int z, int direction, int frame, Viewport viewport) {
         RenderSection section = this.getRenderSection(x, y, z);
 
-        if (section == null || isWithinFrustum(viewport, section)) {
+        if (section == null || !isWithinFrustum(viewport, section)) {
             return;
         }