timer/seq: fix minor issues

alsa-project/alsa-gobject pull request #85 was opened from takaswie:

As long as building on Ubuntu 25.04, some codes takes warnings from gcc 14 and gi-docgen 2025.3-1. This patchset includes some fixes to solve the codes.

Request URL : https://github.com/alsa-project/alsa-gobject/pull/85 Patch URL : https://github.com/alsa-project/alsa-gobject/pull/85.patch Repository URL: https://github.com/alsa-project/alsa-gobject