Fix an overflow issue for HBD
Fix an overflow issue for HBD

The sum of squared value of a block can overflow 32bit, this commit
changes to use int64_t to avoid the overflow issue.

Change-Id: I78fcd6999634f186f86d649cfce85d97a993d040

mbebenita/aom,luctrudeau/aom,smarter/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom,smarter/aom,smarter/aom,smarter/aom,GrokImageCompression/aom,mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,mbebenita/aom,luctrudeau/aom,smarter/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,GrokImageCompression/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom