Implement a small LTC optimization

Assets/ScriptableRenderLoop/ShaderLibrary/AreaLighting.hlsl

             L[3] = normalize(L[3]);
             L4   = L[0];
             break;
-        default: // 1, 2, 5
+        case 5:
             L[3] = normalize(L[3]);
             L4   = normalize(L4);
             break;
     if (n == 5)
         sum += IntegrateEdge(L4, L[0]);
 
-    sum *= INV_TWO_PI; // Normalization of the integral of cosine over the sphere
+    sum *= INV_TWO_PI; // Normalization
 
     return twoSided ? abs(sum) : max(sum, 0.0);
 }