Switch default kernel directory and change build flag naming

Bug: 309749142
Change-Id: Ifaeab036656e0a5aac391fa18a495deb5b686fec

device-lynx.mk

@@ -14,18 +14,10 @@
 # limitations under the License.
 #
 
-ifdef RELEASE_GOOGLE_LYNX_KERNEL_VERSION
-TARGET_LINUX_KERNEL_VERSION := $(RELEASE_GOOGLE_LYNX_KERNEL_VERSION)
-endif
-
-ifdef RELEASE_GOOGLE_LYNX_KERNEL_DIR
+TARGET_LINUX_KERNEL_VERSION := $(RELEASE_KERNEL_LYNX_VERSION)
 # Keeps flexibility for kasan and ufs builds
-TARGET_KERNEL_DIR ?= $(RELEASE_GOOGLE_LYNX_KERNEL_DIR)
-TARGET_BOARD_KERNEL_HEADERS ?= $(RELEASE_GOOGLE_LYNX_KERNEL_DIR)/kernel-headers
-else
-TARGET_KERNEL_DIR ?= device/google/lynx-kernel
-TARGET_BOARD_KERNEL_HEADERS ?= device/google/lynx-kernel/kernel-headers
-endif
+TARGET_KERNEL_DIR ?= $(RELEASE_KERNEL_LYNX_DIR)
+TARGET_BOARD_KERNEL_HEADERS ?= $(RELEASE_KERNEL_LYNX_DIR)/kernel-headers
 
 $(call inherit-product-if-exists, vendor/google_devices/lynx/prebuilts/device-vendor-lynx.mk)
 $(call inherit-product-if-exists, vendor/google_devices/gs201/prebuilts/device-vendor.mk)