gpu: Stop using deprecated spirv-tools var

Change-Id: I4e0b6f59e53bf6873cfc6d1f4d74383e564b33ee
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/Vulkan-ValidationLayers/+/430544
Reviewed-by: John Bauman <jbauman@google.com>
Reviewed-by: John Rosasco <rosasco@google.com>
diff --git a/layers/gpu_validation.cpp b/layers/gpu_validation.cpp
index abaab00..efb6a2f 100644
--- a/layers/gpu_validation.cpp
+++ b/layers/gpu_validation.cpp
@@ -237,7 +237,7 @@
     device_gpu_assisted->shaderInt64 = device_gpu_assisted->enabled_features.core.shaderInt64;
     device_gpu_assisted->physicalDevice = physicalDevice;
     device_gpu_assisted->device = *pDevice;
-    device_gpu_assisted->output_buffer_size = sizeof(uint32_t) * (spvtools::kInst2MaxOutCnt + 1);
+    device_gpu_assisted->output_buffer_size = sizeof(uint32_t) * (spvtools::kInstMaxOutCnt + 1);
     std::vector<VkDescriptorSetLayoutBinding> bindings;
     VkDescriptorSetLayoutBinding binding = {0, VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, 1,
                                             VK_SHADER_STAGE_ALL_GRAPHICS | VK_SHADER_STAGE_COMPUTE_BIT | kShaderStageAllRayTracing,