Qt: Disable LTCG on Release-only builds

It wasn't being used anyway.

src/duckstation-qt/duckstation-qt.vcxproj

@@ -383,6 +383,7 @@
       <OptimizeReferences>true</OptimizeReferences>
       <AdditionalLibraryDirectories>$(SolutionDir)dep\msvc\lib32;$(SolutionDir)dep\msvc\qt5-x86\lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <AdditionalDependencies>Qt5Core.lib;Qt5Gui.lib;Qt5Widgets.lib;Qt5Network.lib;d3d11.lib;dxgi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <LinkTimeCodeGeneration>Default</LinkTimeCodeGeneration>
     </Link>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='ReleaseLTCG|Win32'">
@@ -429,6 +430,7 @@
       <OptimizeReferences>true</OptimizeReferences>
       <AdditionalLibraryDirectories>$(SolutionDir)dep\msvc\lib64;$(SolutionDir)dep\msvc\qt5-x64\lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <AdditionalDependencies>Qt5Core.lib;Qt5Gui.lib;Qt5Widgets.lib;Qt5Network.lib;d3d11.lib;dxgi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <LinkTimeCodeGeneration>Default</LinkTimeCodeGeneration>
     </Link>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='ReleaseLTCG|x64'">