PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS: allow inheritance

Test: with this is true, build
     `verified_assembled_system_matrix.xml`;
      file includes kernel requirements
Change-Id: I833b4fefabefb2f0457171055afe5722981e3589
diff --git a/core/config.mk b/core/config.mk
index 9e227e6..e03dbf3 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -923,12 +923,7 @@
     PLATFORM_SEPOLICY_VERSION \
     TOT_SEPOLICY_VERSION \
 
-# If true, kernel configuration requirements are present in OTA package (and will be enforced
-# during OTA). Otherwise, kernel configuration requirements are enforced in VTS.
-# Devices that checks the running kernel (instead of the kernel in OTA package) should not
-# set this variable to prevent OTA failures.
-ifndef PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS
-  PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS :=
+ifeq ($(PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS),)
   ifdef PRODUCT_SHIPPING_API_LEVEL
     ifeq (true,$(call math_gt_or_eq,$(PRODUCT_SHIPPING_API_LEVEL),29))
       PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS := true
diff --git a/core/product.mk b/core/product.mk
index 661416c..df849b0 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -212,6 +212,7 @@
     PRODUCT_FORCE_PRODUCT_MODULES_TO_SYSTEM_PARTITION \
     PRODUCT_USE_DYNAMIC_PARTITIONS \
     PRODUCT_RETROFIT_DYNAMIC_PARTITIONS \
+    PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS \
 
 define dump-product
 $(info ==== $(1) ====)\
diff --git a/core/product_config.mk b/core/product_config.mk
index 5a727c4..45357cf 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -546,3 +546,10 @@
 PRODUCT_FORCE_PRODUCT_MODULES_TO_SYSTEM_PARTITION := \
     $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_FORCE_PRODUCT_MODULES_TO_SYSTEM_PARTITION))
 .KATI_READONLY := PRODUCT_FORCE_PRODUCT_MODULES_TO_SYSTEM_PARTITION
+
+# If set, kernel configuration requirements are present in OTA package (and will be enforced
+# during OTA). Otherwise, kernel configuration requirements are enforced in VTS.
+# Devices that checks the running kernel (instead of the kernel in OTA package) should not
+# set this variable to prevent OTA failures.
+PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS := \
+    $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS))