fixed: mip to use for SSReflection

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.hlsl

     {
         rayOriginWS             = posInput.positionWS;
         rayDirWS                = preLightData.iblR;
-        mipLevel                = preLightData.transparentSSMipLevel;
+        mipLevel                = PerceptualRoughnessToMipmapLevel(preLightData.iblPerceptualRoughness);
         invScreenWeightDistance = _SSReflectionInvScreenWeightDistance;
 #if DEBUG_DISPLAY
         debugMode               = DEBUGLIGHTINGMODE_SCREEN_SPACE_TRACING_REFLECTION;