SL-17274: PBR: Cleanup: Only calc reflectance if debugging

indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl

@@ -239,7 +239,9 @@ void main()
         vec3  colorDiff      = mix( diffuse.rgb, vec3(0)    , metal);
               reflect0       = mix( reflect0   , diffuse.rgb, metal); // reflect at 0 degrees
               reflect90      = vec3(1);                               // reflect at 90 degrees
+#if DEBUG_PBR_REFLECTANCE
         float reflectance    = max( max( reflect0.r, reflect0.g ), reflect0.b );
+#endif
 
         // Common to RadianceGGX and RadianceLambertian
         float specWeight = 1.0;