Add a cast to avoid a Visual Studio build warning
Add a cast to avoid a Visual Studio build warning

Change-Id: I82fe5145b83c690bff50e4104adcf22aeb973903

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom