Remove unused make variable BUILDING_PVMFW_IMAGE

Test: CIs
Change-Id: I56d72c08c1fe5794f8c550651a2805109b70391f
diff --git a/core/board_config.mk b/core/board_config.mk
index 16acdde..e895b6c 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -922,12 +922,6 @@
 endif
 .KATI_READONLY := BOARD_USES_PVMFWIMAGE
 
-BUILDING_PVMFW_IMAGE :=
-ifeq ($(PRODUCT_BUILD_PVMFW_IMAGE),true)
-  BUILDING_PVMFW_IMAGE := true
-endif
-.KATI_READONLY := BUILDING_PVMFW_IMAGE
-
 ###########################################
 # Ensure consistency among TARGET_RECOVERY_UPDATER_LIBS, AB_OTA_UPDATER, and PRODUCT_OTA_FORCE_NON_AB_PACKAGE.
 TARGET_RECOVERY_UPDATER_LIBS ?=
diff --git a/core/config.mk b/core/config.mk
index a6266b8..91c8bd8 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -166,6 +166,7 @@
 $(KATI_obsolete_var PRODUCT_SUPPORTS_BOOT_SIGNER,VB 1.0 and related variables are no longer supported)
 $(KATI_obsolete_var PRODUCT_VERITY_SIGNING_KEY,VB 1.0 and related variables are no longer supported)
 $(KATI_obsolete_var BOARD_PREBUILT_PVMFWIMAGE,pvmfw.bin is now built in AOSP and custom versions are no longer supported)
+$(KATI_obsolete_var BUILDING_PVMFW_IMAGE,BUILDING_PVMFW_IMAGE is no longer used)
 $(KATI_obsolete_var BOARD_BUILD_SYSTEM_ROOT_IMAGE)
 
 # Used to force goals to build.  Only use for conditionally defined goals.