project-lakitu: use cos-linux-mod class for loadpin-trigger

Convert loadpin-trigger ebuild to using cos-linux-mod eclass.
This change fixes building the module for kernel 5.10 on ARM64

BUG=b/186269275
TEST=presubmit
RELEASE_NOTE=None

Change-Id: I79cfca2723f0bb9502369640545d57de9f729bfc
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/16033
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-by: Roy Yang <royyang@google.com>
2 files changed