Fixed issue that was causing rendering of camera with viewport other than default to fail with msaa disabled.

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightPipeline.cs

             Rect cameraRect = m_CurrCamera.rect;
             if (!(Math.Abs(cameraRect.x) > 0.0f || Math.Abs(cameraRect.y) > 0.0f || Math.Abs(cameraRect.width) < 1.0f || Math.Abs(cameraRect.height) < 1.0f))
                 configuration |= FrameRenderingConfiguration.DefaultViewport;
+            else
+                intermediateTexture = true;
 
             if (intermediateTexture)
                 configuration |= FrameRenderingConfiguration.IntermediateTexture;