v3dv: amend vkEnumerateInstanceExtensionProperties to handle layers

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
diff --git a/src/broadcom/vulkan/v3dv_device.c b/src/broadcom/vulkan/v3dv_device.c
index 8a15f6c..1a43985 100644
--- a/src/broadcom/vulkan/v3dv_device.c
+++ b/src/broadcom/vulkan/v3dv_device.c
@@ -67,6 +67,10 @@
                                           uint32_t *pPropertyCount,
                                           VkExtensionProperties *pProperties)
 {
+   /* We don't support any layers  */
+   if (pLayerName)
+      return vk_error(NULL, VK_ERROR_LAYER_NOT_PRESENT);
+
    VK_OUTARRAY_MAKE(out, pProperties, pPropertyCount);
 
    for (int i = 0; i < V3DV_INSTANCE_EXTENSION_COUNT; i++) {