Migrate some vp9 highbd intrapred x86 speedup to av1

Function speedup on i7-6700:
D117   sse2   ssse3
4x4    ~1.8x
8x8           ~3.4x
16x16         ~5.5x
32x32         ~2.9x

D135   sse2   ssse3
4x4    ~1.9
8x8           ~3.3x
16x16         ~5.3x
32x32         ~3.6x

D153   sse2   ssse3
4x4    ~1.9x
8x8           ~2.8x
16x16         ~5.5x
32x32         ~3.6x

Change-Id: I43ab5fa8dcbcfa51acbde554abf3e5d7d336f391
diff --git a/aom_dsp/aom_dsp.cmake b/aom_dsp/aom_dsp.cmake
index ab2e36f..dc8d24a 100644
--- a/aom_dsp/aom_dsp.cmake
+++ b/aom_dsp/aom_dsp.cmake
@@ -239,6 +239,10 @@
       "${AOM_ROOT}/aom_dsp/x86/highbd_intrapred_sse2.c"
       "${AOM_ROOT}/aom_dsp/x86/highbd_loopfilter_sse2.c")
 
+  set(AOM_DSP_COMMON_INTRIN_SSSE3
+      ${AOM_DSP_COMMON_INTRIN_SSSE3}
+      "${AOM_ROOT}/aom_dsp/x86/highbd_intrapred_ssse3.c")
+
   set(AOM_DSP_COMMON_INTRIN_AVX2
       ${AOM_DSP_COMMON_INTRIN_AVX2}
       "${AOM_ROOT}/aom_dsp/x86/highbd_convolve_avx2.c"