Fixed issue that was causing the attenuation to be applied to direcitonal lights when using attenuation texture.

ScriptableRenderPipeline/LightweightPipeline/LightweightPipeline.cs

             lightColor = light.finalColor;
 
             float rangeSq = light.range * light.range;
-            float quadAtten = (light.lightType == LightType.Directional) ? 0.0f : 25.0f / rangeSq;
+            float quadAtten = 0.0f;
+            if (light.lightType != LightType.Directional)
+                quadAtten = (m_Asset.AttenuationTexture != null) ? 1.0f : 25.0f / rangeSq;
 
             if (light.lightType == LightType.Spot)
             {

ScriptableRenderPipeline/LightweightPipeline/Shaders/LightweightPipelineLighting.cginc

     float3 posToLightVec = lightInput.pos.xyz - worldPos * lightInput.pos.w;
     float distanceSqr = max(dot(posToLightVec, posToLightVec), 0.001);
 
+    // TODO: Test separating dir lights into diff loop by sorting on the pipe and setting -1 on LightIndexMap.
-    float lightAtten = tex2D(_AttenuationTexture, float2(distanceSqr / attenuationParams.w, 0.0)).a;
+    float u = (distanceSqr * attenuationParams.z) / attenuationParams.w;
+    float lightAtten = tex2D(_AttenuationTexture, float2(u, 0.0)).a;
 #else
     //// attenuationParams.z = kQuadFallOff = (25.0) / (lightRange * lightRange)
     //// attenuationParams.w = lightRange * lightRange