Fix dawn.node compilation

Fix the use of DawnTogglesDeviceDescriptor.
The dawn.node GPUAdaptor binindg code is already in the wgpu namespace
so use DawnTogglesDeviceDescriptor directly instead of prefixing
it with wgpu::

Bug: dawn:160
Change-Id: I01ab76983aabe150df5769764735d90e4f1e73bb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/74840
Auto-Submit: David Neto <dneto@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>

src/dawn_node/binding/GPUAdapter.cpp

@@ -218,7 +218,7 @@ namespace wgpu { namespace binding {
         desc.requiredFeaturesCount = requiredFeatures.size();
         desc.requiredFeatures = requiredFeatures.data();
 
-        wgpu::DawnDeviceTogglesDescriptor togglesDesc = {};
+        DawnTogglesDeviceDescriptor togglesDesc = {};
         desc.nextInChain = &togglesDesc;
         togglesDesc.forceEnabledTogglesCount = forceEnabledToggles.size();
         togglesDesc.forceEnabledToggles = forceEnabledToggles.data();