VP9 common for ARMv8 by using NEON intrinsics 02

Add vp9_avg_neon.c
- vp9_convolve_avg_neon

Change-Id: Id2c9d5bcfa37cff1a16417aba1656ff07bdf10fd
Signed-off-by: James Yu <james.yu@linaro.org>
diff --git a/test/convolve_test.cc b/test/convolve_test.cc
index 6c68e6a..12ac4c3 100644
--- a/test/convolve_test.cc
+++ b/test/convolve_test.cc
@@ -1758,12 +1758,20 @@
     make_tuple(64, 64, &convolve8_avx2)));
 #endif  // HAVE_AVX2 && HAVE_SSSE3
 
+#if HAVE_NEON
 #if HAVE_NEON_ASM
 const ConvolveFunctions convolve8_neon(
     vp9_convolve_copy_neon, vp9_convolve_avg_neon,
     vp9_convolve8_horiz_neon, vp9_convolve8_avg_horiz_neon,
     vp9_convolve8_vert_neon, vp9_convolve8_avg_vert_neon,
     vp9_convolve8_neon, vp9_convolve8_avg_neon, 0);
+#else  // HAVE_NEON
+const ConvolveFunctions convolve8_neon(
+    vp9_convolve_copy_c, vp9_convolve_avg_neon,
+    vp9_convolve8_horiz_c, vp9_convolve8_avg_horiz_c,
+    vp9_convolve8_vert_c, vp9_convolve8_avg_vert_c,
+    vp9_convolve8_c, vp9_convolve8_avg_c, 0);
+#endif  // HAVE_NEON_ASM
 
 INSTANTIATE_TEST_CASE_P(NEON, ConvolveTest, ::testing::Values(
     make_tuple(4, 4, &convolve8_neon),
@@ -1779,7 +1787,7 @@
     make_tuple(64, 32, &convolve8_neon),
     make_tuple(32, 64, &convolve8_neon),
     make_tuple(64, 64, &convolve8_neon)));
-#endif
+#endif  // HAVE_NEON
 
 #if HAVE_DSPR2
 const ConvolveFunctions convolve8_dspr2(