wrong Scale values

[GregSlazinski]

https://github.com/NVIDIAGameWorks/Falcor/blob/master/Framework/Source/Utils/Platform/Windows/Windows.cpp#L279

 case SCALE_175_PERCENT: return 1.70f;
 case SCALE_500_PERCENT: return 4.60f;

[nbentyNV]

We should convert that switch(factor) to `float(factor)*0.01f;