HDRenderPipeline: Fix fog after merge issue

ScriptableRenderPipeline/HDRenderPipeline/ShaderPass/ShaderPassForward.hlsl

         LightLoop(V, posInput, preLightData, bsdfData, bakeDiffuseLighting, featureFlags, diffuseLighting, specularLighting);
 
         outColor = ApplyBlendModeAccurateLighting(diffuseLighting, specularLighting, builtinData.opacity);
+        outColor = EvaluateAtmosphericScattering(posInput, outColor);
     }
 
 #ifdef _DEPTHOFFSET_ON

ScriptableRenderPipeline/HDRenderPipeline/ShaderPass/ShaderPassForwardUnlit.hlsl

     BSDFData bsdfData = ConvertSurfaceDataToBSDFData(surfaceData);
 
     // TODO: we must not access bsdfData here, it break the genericity of the code!
-    float4 outColor = EvaluateAtmosphericScattering(posInput, float4(bsdfData.color + builtinData.emissiveColor, builtinData.opacity));
+    float4 outColor = float4(bsdfData.color + builtinData.emissiveColor, builtinData.opacity);
+    outColor = EvaluateAtmosphericScattering(posInput, outColor);
 
 #ifdef DEBUG_DISPLAY
     // Same code in ShaderPassForward.shader