Remove dependencies on removed xf86-video-modesetting package

See commits for details.

See also:

• https://gitlab.alpinelinux.org/alpine/aports/-/commit/d121fc7ec1cecb043ae44205b86e09dbdc076407
• https://gitlab.alpinelinux.org/alpine/aports/-/commit/334572a52c662cc213b551ac14960410f5f73195