Fix Visual Studio 12 build Error in sum_squares_2d
Fix Visual Studio 12 build Error in sum_squares_2d

Some versions of Visual Studio don't have the
_mm256_set1_epi64x function. Using __m256i yy_set1_64_from_32i
instead.

BUG=aomedia:2138

Change-Id: Ifcdc804ca069c12e290328ba8b4326050d6234ee

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