Use more efficient parameter clamping

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.shader

 
         [Enum(Standard, 0, Subsurface Scattering, 1, Clear Coat, 2)] _MaterialID("Material Class", Int) = 0
         _SubsurfaceProfile("Subsurface Profile", Int) = 0
-        _SubsurfaceRadius("Subsurface Radius", Range(0.0, 1.0)) = 0.5
+        _SubsurfaceRadius("Subsurface Radius", Range(0.004, 1.0)) = 0.5
-        _Thickness("Thickness", Range(0.0, 1.0)) = 0.5
+        _Thickness("Thickness", Range(0.004, 1.0)) = 0.5
         _ThicknessMap("Thickness Map", 2D) = "white" {}
 
         //_CoatCoverage("CoatCoverage", Range(0.0, 1.0)) = 0

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/LitTessellation.shader

 
         [Enum(Standard, 0, Subsurface Scattering, 1, Clear Coat, 2)] _MaterialID("Material Class", Int) = 0
         _SubsurfaceProfile("Subsurface Profile", Int) = 0
-        _SubsurfaceRadius("Subsurface Radius", Range(0.0, 1.0)) = 0.5
+        _SubsurfaceRadius("Subsurface Radius", Range(0.004, 1.0)) = 0.5
-        _Thickness("Thickness", Range(0.0, 1.0)) = 0.5
+        _Thickness("Thickness", Range(0.004, 1.0)) = 0.5
         _ThicknessMap("Thickness Map", 2D) = "white" {}
 
         //_CoatCoverage("CoatCoverage", Range(0.0, 1.0)) = 0

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/CombineSubsurfaceScattering.shader

 
                 float2 gBufferData  = LOAD_TEXTURE2D(_GBufferTexture2, posInput.unPositionSS).ra;
                 int    profileID    = int(gBufferData.y * N_PROFILES);
-                float  distScale    = max(0.0001, gBufferData.x * 0.01);
+                float  distScale    = gBufferData.x * 0.01;
                 float  invDistScale = rcp(distScale);
 
                 // Reconstruct the view-space position.