sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Convert the PCI ID selection from a simple if into a table.
Mark the table with PNP info.
Fix compilation by returning FILTER_STRAY in two places, as suggested by comments.
Create a simple module from this. Left unconnected because I can't test it as a module.