Remove unused highbd_ihalfcenter32_c function
Remove unused highbd_ihalfcenter32_c function

Change-Id: I4390fcbdf353d79dadc021d83d40891e518997dc

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