Disable ssse3 version idct16x16_256_add()

The version is currently producing different result from c version
for some input. Disable the use of it for now to allow time for
investigation the source of mismatch.

Change-Id: Id039455494ee531db4886a9f1fa4761174ef6df3

test/dct16x16_test.cc

@@ -933,12 +933,4 @@ INSTANTIATE_TEST_CASE_P(
         make_tuple(&idct16x16_12,
                    &idct16x16_256_add_12_sse2, 3167, VPX_BITS_12)));
 #endif  // HAVE_SSE2 && CONFIG_VP9_HIGHBITDEPTH && !CONFIG_EMULATE_HARDWARE
-
-#if HAVE_SSSE3 && !CONFIG_VP9_HIGHBITDEPTH && !CONFIG_EMULATE_HARDWARE
-INSTANTIATE_TEST_CASE_P(
-    SSSE3, Trans16x16DCT,
-    ::testing::Values(
-        make_tuple(&vp9_fdct16x16_c, &vp9_idct16x16_256_add_ssse3, 0,
-                   VPX_BITS_8)));
-#endif  // HAVE_SSSE3 && !CONFIG_VP9_HIGHBITDEPTH && !CONFIG_EMULATE_HARDWARE
 }  // namespace

vp9/common/vp9_rtcd_defs.pl

@@ -437,7 +437,7 @@ if (vpx_config("CONFIG_VP9_HIGHBITDEPTH") eq "yes") {
     specialize qw/vp9_idct16x16_1_add sse2 neon dspr2/;
 
     add_proto qw/void vp9_idct16x16_256_add/, "const tran_low_t *input, uint8_t *dest, int dest_stride";
-    specialize qw/vp9_idct16x16_256_add sse2 ssse3 neon dspr2/;
+    specialize qw/vp9_idct16x16_256_add sse2 neon dspr2/;
 
     add_proto qw/void vp9_idct16x16_10_add/, "const tran_low_t *input, uint8_t *dest, int dest_stride";
     specialize qw/vp9_idct16x16_10_add sse2 ssse3 neon dspr2/;