Using BOARD_AVB_VBMETA_VENDOR_IMAGE_ARGS for vbmeta_vendor.img

The value of BOARD_AVB_VBMETA_SYSTEM_IMAGE_ARGS and
BOARD_AVB_VBMETA_VENDOR_IMAGE_ARGS are usually the same, e.g.,
--padding_size 4096 --rollback_index 1656979200.

However, in a split build, the value of
BOARD_AVB_VBMETA_SYSTEM_IMAGE_ARGS might be empty.
Using BOARD_AVB_VBMETA_VENDOR_IMAGE_ARGS to correctly
assign the value for vbmeta_vendor.img.

Bug: 232360330
Test: TreeHugger
Change-Id: Ia26816bd309084c3a4c0df6b9f2f3fc5a28bc31a
diff --git a/core/Makefile b/core/Makefile
index a6f6dd2..86324cb 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -5238,7 +5238,7 @@
 endif # BOARD_AVB_VBMETA_SYSTEM
 ifneq (,$(strip $(BOARD_AVB_VBMETA_VENDOR)))
 	$(hide) echo "avb_vbmeta_vendor=$(BOARD_AVB_VBMETA_VENDOR)" >> $@
-	$(hide) echo "avb_vbmeta_vendor_args=$(BOARD_AVB_MAKE_VBMETA_SYSTEM_IMAGE_ARGS)" >> $@
+	$(hide) echo "avb_vbmeta_vendor_args=$(BOARD_AVB_MAKE_VBMETA_VENDOR_IMAGE_ARGS)" >> $@
 	$(hide) echo "avb_vbmeta_vendor_key_path=$(BOARD_AVB_VBMETA_VENDOR_KEY_PATH)" >> $@
 	$(hide) echo "avb_vbmeta_vendor_algorithm=$(BOARD_AVB_VBMETA_VENDOR_ALGORITHM)" >> $@
 	$(hide) echo "avb_vbmeta_vendor_rollback_index_location=$(BOARD_AVB_VBMETA_VENDOR_ROLLBACK_INDEX_LOCATION)" >> $@