Fix CMake desync with configure build.

Just missed the addition of av1_highbd_quantize_avx2.c in
b962dbb276e609792c40776e79e692f20fbf6fa2.

Change-Id: Ieb2324fc3a8e26be3bd7e190b036a785c39dfa5d
diff --git a/av1/av1.cmake b/av1/av1.cmake
index 8bc9a57..80d860e 100644
--- a/av1/av1.cmake
+++ b/av1/av1.cmake
@@ -218,6 +218,10 @@
       ${AOM_AV1_ENCODER_INTRIN_SSE4_1}
       "${AOM_ROOT}/av1/encoder/x86/av1_highbd_quantize_sse4.c"
       "${AOM_ROOT}/av1/encoder/x86/highbd_fwd_txfm_sse4.c")
+
+  set(AOM_AV1_ENCODER_INTRIN_AVX2
+      ${AOM_AV1_ENCODER_INTRIN_AVX2}
+      "${AOM_ROOT}/av1/encoder/x86/av1_highbd_quantize_avx2.c")
 else ()
   set(AOM_AV1_COMMON_INTRIN_NEON
       ${AOM_AV1_COMMON_INTRIN_NEON}