kernel: use systemimage_intermediates on devices with no vendor

Change I8b6040e03589bde2af4e161c891ded237a9bb335 did not account for
devices without a separate vendor partition, causing build to fail with
the following:

FAILED: ninja: '/file_list.txt', needed by 'out/target/product/joan/obj/KERNEL_OBJ/arch/arm64/boot/Image.gz-dtb', missing and no known rule to make it

Use systemimage_intermediates instead on said devices.

Test: m kernel
Co-authored-by: Bruno Martins <bgcngm@gmail.com>
Change-Id: If9eb75a1bef98345e9c137c2463e392d50be239b
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 863289f..a5fc94f 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -419,7 +419,11 @@
 KERNEL_MODULES_OUT := $(TARGET_OUT_VENDOR)
 KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_vendor)
 KERNEL_MODULE_MOUNTPOINT := vendor
+ifneq ($(BUILDING_VENDOR_IMAGE),)
 KERNEL_MODULES_PARTITION_FILE_LIST := $(vendorimage_intermediates)/file_list.txt
+else # No vendor partition
+KERNEL_MODULES_PARTITION_FILE_LIST := $(systemimage_intermediates)/file_list.txt
+endif # BUILDING_VENDOR_IMAGE
 $(INSTALLED_VENDORIMAGE_TARGET): $(TARGET_PREBUILT_INT_KERNEL)
 endif
 ifeq ($(BOARD_USES_SYSTEM_DLKMIMAGE),true)