Remove hardcoded TARGET_PREFER_32_BIT_APPS.

This isn't required any longer, besides individual products
should be allowed to set this value themselves.

Change-Id: I684edf073b5c19f412b4617f8aa22824193c19be
diff --git a/CleanSpec.mk b/CleanSpec.mk
index e9af8b3..8052267 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -243,6 +243,9 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
 
+# Unset TARGET_PREFER_32_BIT_APPS for 64 bit targets.
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************