Remove remaining references to mbgraph

Change-Id: Idaafe3d3a27e6936e225bb48913c2e851bff69b9
diff --git a/av1/av1.cmake b/av1/av1.cmake
index 51e1826..9486ba8 100644
--- a/av1/av1.cmake
+++ b/av1/av1.cmake
@@ -407,8 +407,6 @@
                    "${AOM_ROOT}/av1/encoder/firstpass.h"
                    "${AOM_ROOT}/av1/encoder/gop_structure.c"
                    "${AOM_ROOT}/av1/encoder/gop_structure.h"
-                   "${AOM_ROOT}/av1/encoder/mbgraph.c"
-                   "${AOM_ROOT}/av1/encoder/mbgraph.h"
                    "${AOM_ROOT}/av1/encoder/partition_cnn_weights.h"
                    "${AOM_ROOT}/av1/encoder/partition_model_weights.h"
                    "${AOM_ROOT}/av1/encoder/pass2_strategy.c"