radv/rt: Correctly copy culling flags when updating to separate AS

This was missing and led to the field being uninitialized.

Cc: mesa-stable
(cherry picked from commit b7f011e653)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38803>

.pick_status.json

@@ -2344,7 +2344,7 @@
         "description": "radv/rt: Correctly copy culling flags when updating to separate AS",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/amd/vulkan/bvh/update.comp

@@ -95,6 +95,8 @@ void main() {
         if (!VK_BUILD_FLAG(RADV_BUILD_FLAG_UPDATE_IN_PLACE)) {
             for (uint32_t i = 0; i < 4; ++i)
                 DEREF(dst_node).children[i] = children[i];
+            if (VK_BUILD_FLAG(VK_BUILD_FLAG_PROPAGATE_CULL_FLAGS))
+                DEREF(dst_node).flags = DEREF(src_node).flags;
         }
 
         for (uint32_t i = 0; i < valid_child_count; ++i) {

src/amd/vulkan/radv_acceleration_structure.c

@@ -283,6 +283,9 @@ radv_get_build_config(VkDevice _device, struct vk_acceleration_structure_build_s
    if (state->build_info->geometryCount == 1)
       update_key |= RADV_BUILD_FLAG_UPDATE_SINGLE_GEOMETRY;
 
+   if (device->meta_state.accel_struct_build.build_args.propagate_cull_flags)
+      update_key |= VK_BUILD_FLAG_PROPAGATE_CULL_FLAGS;
+
    state->config.update_key[0] = update_key;
 }