Add framework for building the pvmfw.img partition

Adapt the variables necessary for building pvmfw.img by following what
was done for other Android partitions and introducing:

 - PRODUCT_BUILD_PVMFW_IMAGE
 - BUILDING_PVMFW_IMAGE
 - BUILT_PVMFWIMAGE_TARGET

Replace the manual 'cp' by the more common 'copy-one-file'.

Bug: 199831815
Test: m ${ANDROID_PRODUCT_OUT}/pvmfw.img # with TARGET_PKVM_ENABLED=true
Change-Id: I5e4bbcbdbf4b96281ee54631938f097e9744883c
diff --git a/core/board_config.mk b/core/board_config.mk
index 56c3e71..9c6b5cb 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -699,8 +699,20 @@
 ifdef BOARD_PREBUILT_PVMFWIMAGE
   BOARD_USES_PVMFWIMAGE := true
 endif
+ifeq ($(PRODUCT_BUILD_PVMFW_IMAGE),true)
+  BOARD_USES_PVMFWIMAGE := true
+endif
 .KATI_READONLY := BOARD_USES_PVMFWIMAGE
 
+BUILDING_PVMFW_IMAGE :=
+ifeq ($(PRODUCT_BUILD_PVMFW_IMAGE),true)
+  BUILDING_PVMFW_IMAGE := true
+endif
+ifdef BOARD_PREBUILT_PVMFWIMAGE
+  BUILDING_PVMFW_IMAGE :=
+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 ?=