Allows using optimzed version vp9_fdct8x8

Change-Id: I59cecb7178a93cdee7ad535fa996ef0caa6e988c
diff --git a/vp9/encoder/vp9_psnrhvs.c b/vp9/encoder/vp9_psnrhvs.c
index e10e028..2e7e345 100644
--- a/vp9/encoder/vp9_psnrhvs.c
+++ b/vp9/encoder/vp9_psnrhvs.c
@@ -25,7 +25,7 @@
 
 void od_bin_fdct8x8(tran_low_t *y, int ystride, const int16_t *x, int xstride) {
   (void) xstride;
-  vp9_fdct8x8_c(x, y, ystride);
+  vp9_fdct8x8(x, y, ystride);
 }
 
 /* Normalized inverse quantization matrix for 8x8 DCT at the point of