Wrong index on centroid pixel computation in Pr/PrPixel/src/VPClus.cpp

Branch TDR In Pr/PrPixel/src/VPClus.cpp line 366 367

          const float fx = spcache.fxy[0];
          const float fy = spcache.fxy[1];

have the same indexes as line 339 340.

Looking back to previous versions ~2 months ago indexes were 2 and 3, probably a cut and paste error