raviole: clean up kernel variables am: 83b8bef3e5

Original change: https://googleplex-android-review.googlesource.com/c/device/google/raviole/+/15749498

Change-Id: I47dec91f5e626e0fcb65d636ef9f324580cb3985
diff --git a/device-oriole.mk b/device-oriole.mk
index 8f631e8..2a16c40 100644
--- a/device-oriole.mk
+++ b/device-oriole.mk
@@ -14,7 +14,8 @@
 # limitations under the License.
 #
 
-TARGET_KERNEL_DIR := device/google/raviole-kernel
+TARGET_KERNEL_DIR ?= device/google/raviole-kernel
+TARGET_BOARD_KERNEL_HEADERS := device/google/raviole-kernel/kernel-headers
 
 $(call inherit-product-if-exists, vendor/google_devices/raviole/prebuilts/device-vendor-oriole.mk)
 $(call inherit-product-if-exists, vendor/google_devices/gs101/prebuilts/device-vendor.mk)
diff --git a/device-raven.mk b/device-raven.mk
index adff919..34b4102 100644
--- a/device-raven.mk
+++ b/device-raven.mk
@@ -14,7 +14,8 @@
 # limitations under the License.
 #
 
-TARGET_KERNEL_DIR := device/google/raviole-kernel
+TARGET_KERNEL_DIR ?= device/google/raviole-kernel
+TARGET_BOARD_KERNEL_HEADERS := device/google/raviole-kernel/kernel-headers
 
 $(call inherit-product-if-exists, vendor/google_devices/raviole/prebuilts/device-vendor-raven.mk)
 $(call inherit-product-if-exists, vendor/google_devices/gs101/prebuilts/device-vendor.mk)
diff --git a/device-slider.mk b/device-slider.mk
index 0d2cf6a..add112d 100644
--- a/device-slider.mk
+++ b/device-slider.mk
@@ -14,7 +14,8 @@
 # limitations under the License.
 #
 
-TARGET_KERNEL_DIR := device/google/raviole-kernel
+TARGET_KERNEL_DIR ?= device/google/raviole-kernel
+TARGET_BOARD_KERNEL_HEADERS := device/google/raviole-kernel/kernel-headers
 
 $(call inherit-product-if-exists, vendor/google_devices/raviole/prebuilts/device-vendor-slider.mk)
 $(call inherit-product-if-exists, vendor/google_devices/gs101/prebuilts/device-vendor.mk)
diff --git a/device-whitefin.mk b/device-whitefin.mk
index fc243c2..0820f67 100644
--- a/device-whitefin.mk
+++ b/device-whitefin.mk
@@ -14,7 +14,8 @@
 # limitations under the License.
 #
 
-TARGET_KERNEL_DIR := device/google/raviole-kernel
+TARGET_KERNEL_DIR ?= device/google/raviole-kernel
+TARGET_BOARD_KERNEL_HEADERS := device/google/raviole-kernel/kernel-headers
 
 $(call inherit-product-if-exists, vendor/google_devices/raviole/prebuilts/device-vendor-whitefin.mk)
 $(call inherit-product-if-exists, vendor/google_devices/gs101/prebuilts/device-vendor.mk)