Remove $FreeBSD$: one-line sh pattern

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

- remove non-existent input directories from the configs
- add the target-arch to the project name where applicable (arch dependend code)
- fix comment for __FreeBSD__ [1]

Noticed by: bz [1]

Mechanically add a config for all missing drivers.

No cross-referencing was added to the configs, so no
automatic linking to the documentation of other subsystems.

Drivers which already contain doxygen markup:
agp ath bktr bxe cxgb cxgbe dpt drm e1000 iir
ixgbe mwl nxge ofw pccard siba wpi xen