Suppress implicit-fallthrough warnings.

Bug: b/112564944
Test: build with global -Wimplicit-fallthrough
Change-Id: Ib04daba08bc450657ab8997959a25fe99d3c1d48
diff --git a/vulkan/vkjson/vkjson.cc b/vulkan/vkjson/vkjson.cc
index 6200383..efe622d 100644
--- a/vulkan/vkjson/vkjson.cc
+++ b/vulkan/vkjson/vkjson.cc
@@ -766,6 +766,7 @@
                          &device->external_fence_properties) &&
           visitor->Visit("externalSemaphoreProperties",
                          &device->external_semaphore_properties);
+      FALLTHROUGH_INTENDED;
     case VK_API_VERSION_1_0:
       ret &= visitor->Visit("properties", &device->properties) &&
              visitor->Visit("features", &device->features) &&
@@ -786,6 +787,7 @@
   switch (instance->api_version ^ VK_VERSION_PATCH(instance->api_version)) {
     case VK_API_VERSION_1_1:
       ret &= visitor->Visit("deviceGroups", &instance->device_groups);
+      FALLTHROUGH_INTENDED;
     case VK_API_VERSION_1_0:
       ret &= visitor->Visit("layers", &instance->layers) &&
              visitor->Visit("extensions", &instance->extensions) &&