Remove unsued code in lit.hlsl

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.hlsl

 
     if (overrideNormal)
     {
-        float overrideNormalValue = _DebugLightingNormal.yzw;
         surfaceData.normalWS = worldToTangent[2];
     }
 #endif