Add definition for aom_fdct_8x8_neon.

optimization already existed.

Change-Id: I969c7af8d3001a522ba281165bb00a32e8bb069b
diff --git a/aom_dsp/aom_dsp_rtcd_defs.pl b/aom_dsp/aom_dsp_rtcd_defs.pl
index d482228..1680d5f 100755
--- a/aom_dsp/aom_dsp_rtcd_defs.pl
+++ b/aom_dsp/aom_dsp_rtcd_defs.pl
@@ -481,7 +481,7 @@
 #
 if (aom_config("CONFIG_AV1_ENCODER") eq "yes"){
     add_proto qw/void aom_fdct8x8/, "const int16_t *input, tran_low_t *output, int stride";
-    specialize qw/aom_fdct8x8 sse2/, "$ssse3_x86_64";
+    specialize qw/aom_fdct8x8 neon sse2/, "$ssse3_x86_64";
     # High bit depth
     if (aom_config("CONFIG_AV1_HIGHBITDEPTH") eq "yes") {
       add_proto qw/void aom_highbd_fdct8x8/, "const int16_t *input, tran_low_t *output, int stride";