geom: dont updateGeometryOccupancyAtlasOccChild() when atlas disabled

This commit fixes the ability to code with neighbourAvailBoundaryLog2=0,
which correctly disabled the contextualisation based on externally
adjacent child neighbours, but failed to disable the atlas update.

tmc3/geometry_octree_decoder.cpp

@@ -476,8 +476,10 @@ decodeGeometryOctree(
     assert(occupancy > 0);
 
     // update atlas for advanced neighbours
-    updateGeometryOccupancyAtlasOccChild(
-      node0.pos, nodeSizeLog2, occupancy, &occupancyAtlas);
+    if (gps.neighbour_avail_boundary_log2) {
+      updateGeometryOccupancyAtlasOccChild(
+        node0.pos, nodeSizeLog2, occupancy, &occupancyAtlas);
+    }
 
     // population count of occupancy for IDCM
     int numOccupied = popcnt(occupancy);

tmc3/geometry_octree_encoder.cpp

@@ -497,8 +497,10 @@ encodeGeometryOctree(
     }
 
     // update atlas for advanced neighbours
-    updateGeometryOccupancyAtlasOccChild(
-      node0.pos, nodeSizeLog2, occupancy, &occupancyAtlas);
+    if (gps.neighbour_avail_boundary_log2) {
+      updateGeometryOccupancyAtlasOccChild(
+        node0.pos, nodeSizeLog2, occupancy, &occupancyAtlas);
+    }
 
     // encode child occupancy map
     assert(occupancy > 0);