kernel.mk: correct vndk detection

Change-Id: If0ba85a6a8967783b9c093bacd4e80ef5224f9e2
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index a4bed6b..0b8b81e 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -164,7 +164,7 @@
 KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_system)
 KERNEL_MODULE_MOUNTPOINT := system
 else ifeq ($(NEED_KERNEL_MODULE_VENDOR_OVERLAY),true)
-KERNEL_MODULES_OUT := $(TARGET_OUT_PRODUCT)/vendor_overlay/$(PRODUCT_TARGET_VNDK_VERSION)
+KERNEL_MODULES_OUT := $(TARGET_OUT_PRODUCT)/vendor_overlay/$(PLATFORM_VNDK_VERSION)
 KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_product)
 KERNEL_MODULE_MOUNTPOINT := product
 else