libserialport: drop unused package

BUG=b:187789240
TEST=CQ passes

Change-Id: Ie7788f32d0810d601adfa7917416d21ddae8eab9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/4251541
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Lizzy Presland <zland@google.com>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Lizzy Presland <zland@google.com>
3 files changed