Add deprecation notices for various device drivers removed in 12.0.

This is a direct commit to stable/10 since these files have already
been removed in head.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Sort sections.

Added the missing ``and''.

Add a manual page for the spic(4) device driver and hook it in the build.

Reviewed by: ru