Rename BUILT_PVMFWIMAGE_TARGET to PREBUILT_...

Avoid the name as it is currently confusing given that we're not
actually building the image.

Bug: 216975821
Test: -
Change-Id: Ifac7047e72f590d6acb3997efa20f5f348e39491
diff --git a/core/Makefile b/core/Makefile
index 758e9c5..4f7eb23 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -3646,21 +3646,21 @@
 INTERNAL_PREBUILT_PVMFWIMAGE := packages/modules/Virtualization/pvmfw/pvmfw.img
 
 ifdef BOARD_PREBUILT_PVMFWIMAGE
-BUILT_PVMFWIMAGE_TARGET := $(BOARD_PREBUILT_PVMFWIMAGE)
+PREBUILT_PVMFWIMAGE_TARGET := $(BOARD_PREBUILT_PVMFWIMAGE)
 else ifeq ($(BUILDING_PVMFW_IMAGE),true)
-BUILT_PVMFWIMAGE_TARGET := $(INTERNAL_PREBUILT_PVMFWIMAGE)
+PREBUILT_PVMFWIMAGE_TARGET := $(INTERNAL_PREBUILT_PVMFWIMAGE)
 endif
 
 ifeq ($(BOARD_AVB_ENABLE),true)
-$(INSTALLED_PVMFWIMAGE_TARGET): $(BUILT_PVMFWIMAGE_TARGET) $(AVBTOOL) $(BOARD_AVB_PVMFW_KEY_PATH)
-	cp $(BUILT_PVMFWIMAGE_TARGET) $@
+$(INSTALLED_PVMFWIMAGE_TARGET): $(PREBUILT_PVMFWIMAGE_TARGET) $(AVBTOOL) $(BOARD_AVB_PVMFW_KEY_PATH)
+	cp $< $@
 	$(AVBTOOL) add_hash_footer \
 	    --image $@ \
 	    --partition_size $(BOARD_PVMFWIMAGE_PARTITION_SIZE) \
 	    --partition_name pvmfw $(INTERNAL_AVB_PVMFW_SIGNING_ARGS) \
 	    $(BOARD_AVB_PVMFW_ADD_HASH_FOOTER_ARGS)
 else
-$(eval $(call copy-one-file,$(BUILT_PVMFWIMAGE_TARGET),$(INSTALLED_PVMFWIMAGE_TARGET)))
+$(eval $(call copy-one-file,$(PREBUILT_PVMFWIMAGE_TARGET),$(INSTALLED_PVMFWIMAGE_TARGET)))
 endif
 
 endif # BOARD_USES_PVMFWIMAGE