Obsolete BUILD_BROKEN_PHONY_TARGETS

There are no remaining users.

Test: treehugger
Change-Id: Ice6f25a59265305e7e5d3dd041b16cd04674dd1e
diff --git a/core/board_config.mk b/core/board_config.mk
index e4b88cb..58f636a 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -88,7 +88,6 @@
   BUILD_BROKEN_ANDROIDMK_EXPORTS \
   BUILD_BROKEN_DUP_COPY_HEADERS \
   BUILD_BROKEN_DUP_RULES \
-  BUILD_BROKEN_PHONY_TARGETS \
   BUILD_BROKEN_ENG_DEBUG_TAGS \
   BUILD_BROKEN_USES_NETWORK \
 
diff --git a/core/config.mk b/core/config.mk
index 16cd376..a297f68 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -95,6 +95,7 @@
 $(KATI_deprecated_var USER,Use BUILD_USERNAME instead. See $(CHANGES_URL)#USER)
 $(KATI_obsolete_var TARGET_ROOT_OUT_SBIN,/sbin has been removed, use /system/bin instead)
 $(KATI_obsolete_var TARGET_ROOT_OUT_SBIN_UNSTRIPPED,/sbin has been removed, use /system/bin instead)
+$(KATI_obsolete_var BUILD_BROKEN_PHONY_TARGETS)
 
 # This is marked as obsolete in envsetup.mk after reading the BoardConfig.mk
 $(KATI_deprecate_export It is a global setting. See $(CHANGES_URL)#export_keyword)