Remove TARGET_PREFER_32_BIT.

Bug: https://issuetracker.google.com/138812821
Test: builds
Change-Id: I2ff7793c8b1eb56f6be63375cc7b70aa44254443
diff --git a/core/config.mk b/core/config.mk
index 5be1b86..6bcdda2 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -141,6 +141,7 @@
   TARGET_PROJECT_SYSTEM_INCLUDES \
   2ND_TARGET_PROJECT_SYSTEM_INCLUDES \
   ,Project include variables have been removed)
+$(KATI_obsolete_var TARGET_PREFER_32_BIT TARGET_PREFER_32_BIT_APPS TARGET_PREFER_32_BIT_EXECUTABLES)
 
 # Used to force goals to build.  Only use for conditionally defined goals.
 .PHONY: FORCE
@@ -375,11 +376,6 @@
 include $(BUILD_SYSTEM)/rbe.mk
 endif
 
-ifdef TARGET_PREFER_32_BIT
-TARGET_PREFER_32_BIT_APPS := true
-TARGET_PREFER_32_BIT_EXECUTABLES := true
-endif
-
 # GCC version selection
 TARGET_GCC_VERSION := 4.9
 ifdef TARGET_2ND_ARCH