sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

bhnd: clean up empty lines in .c and .h files

SPDX: license IDs for some ISC-related files.

Bring over the initial rewrite of the broadcom bus support found in their
SoCs and various chips (including, famously, their wifi chips.)

This is "just" (all 20,000 lines of it) code to enumerate the various
versions of busses inside these devices, including the PCI bridge and
the direct SIBA bridge found in MIPS chips.

It also includes shared code for some bus operations (suspend, resume, etc);
EEPROM/SROM/etc parsing and other things that are shared between chips.

Eventually this'll replace the code that bwi/bwn uses for the internal
bus, as well as some apparently upcoming mips74k broadcom SoC support
which uses bwn!

Thanks to Landon Fuller <landonf@landonf.org> for all this work!

Obtained from: https://github.com/landonf/freebsd/compare/user/landonf/bcm4331-CURRENT