Remove unused variable

An upcoming version of clang is more strict on unused variable warnings.

Bug: chromium:332931387
Change-Id: I0eb87a76fcee567639e7fb1a979cb74c3bc75cca
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/183540
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Saifuddin Hitawala <hitawala@chromium.org>
Auto-Submit: Arthur Eubanks <aeubanks@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>
diff --git a/src/dawn/native/Sampler.cpp b/src/dawn/native/Sampler.cpp
index 37a6ecb..ab014af 100644
--- a/src/dawn/native/Sampler.cpp
+++ b/src/dawn/native/Sampler.cpp
@@ -76,7 +76,7 @@
 
     UnpackedPtr<SamplerDescriptor> unpacked = Unpack(descriptor);
 
-    if (auto* vulkanYCbCrDescriptor = unpacked.Get<vulkan::SamplerYCbCrVulkanDescriptor>()) {
+    if (unpacked.Get<vulkan::SamplerYCbCrVulkanDescriptor>()) {
         DAWN_INVALID_IF(!device->HasFeature(Feature::YCbCrVulkanSamplers), "%s is not enabled.",
                         wgpu::FeatureName::YCbCrVulkanSamplers);
     }