D3D12: Fix warn-on-error for unused parameter

Amends 445fb40081

Pick-to: 6.7
Change-Id: Iee3eaffcb7fbbdb3cec8020ee7c9280d52faa0a2
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

src/gui/rhi/qrhid3d12.cpp

@@ -4812,6 +4812,7 @@ bool QD3D12ShaderResourceBindings::create()
 
 void QD3D12ShaderResourceBindings::updateResources(UpdateFlags flags)
 {
+    Q_UNUSED(flags);
     generation += 1;
 }