Remove unused cmake variable (old experiment)

Change-Id: I10a7e9fa4b7cec97650c44bd936c7e9c15337f93
diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index 4928560..c28e225 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -98,7 +98,6 @@
 set(CONFIG_DEPENDENT_HORZTILES 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_DIST_8X8 1 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_ENTROPY_STATS 0 CACHE NUMBER "AV1 experiment flag.")
-set(CONFIG_EOB_FIRST 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_EXT_COMP_REFS 1 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_EXT_DELTA_Q 1 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_EXT_INTRA_MOD 1 CACHE NUMBER "AV1 experiment flag.")