Remove hardcoded TARGET_PREFER_32_BIT_APPS.

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

(cherry picked from commit 7b9347a7f9d870e149ef38438ad547abe2709ee2)

Change-Id: If459eab32c6e7831596224ad3503baefbf028133
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 17fd5d6..7108e10 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -220,6 +220,9 @@
 # Adding dalvik.vm.dex2oat-flags to eng builds
 $(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
 # ************************************************