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

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

bwn(4): migrate bwn(4) to the native bhnd(9) interface, and drop siba_bwn.

- Remove the shim interface that allowed bwn(4) to use either siba_bwn or
bhnd(4), replacing all siba_bwn calls with their bhnd(4) bus equivalents.
- Drop the legay, now-unused siba_bwn bus driver.
- Clean up bhnd(4) board flag defines referenced by bwn(4).

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D13518

Introduce bwn(4) support for the bhnd(4) bus.

Currently, bwn(4) relies on the siba_bwn(4) bus driver to provide support
for the on-chip SSB interconnect found in Broadcom's older PCI(e) Wi-Fi
adapters. Non-PCI Wi-Fi adapters, as well as the newer BCMA interconnect
found in post-2009 Broadcom Wi-Fi hardware, are not supported by
siba_bwn(4).

The bhnd(4) bus driver (also used by the FreeBSD/MIPS Broadcom port)
provides a unified kernel interface to a superset of the hardware supported
by siba_bwn; by attaching bwn(4) via bhnd(4), we can support both modern
PCI(e) Wi-Fi devices based on the BCMA backplane interconnect, as well as
Broadcom MIPS WiSoCs that include a D11 MAC core directly attached to their
SSB or BCMA backplane.

This diff introduces opt-in bwn(4) support for bhnd(4) by providing:

- A small bwn(4) driver subclass, if_bwn_bhnd, that attaches via
bhnd(4) instead of siba_bwn(4).
- A bhndb(4)-based PCI host bridge driver, if_bwn_pci, that optionally
probes at a higher priority than the siba_bwn(4) PCI driver.
- A set of compatibility shims that perform translation of bwn(4)'s
siba_bwn function calls into their bhnd(9) API equivalents when bwn(4)
is attached via a bhnd(4) bus parent. When bwn(4) is attached via
siba_bwn(4), all siba_bwn function calls are simply passed through to
their original implementations.

To test bwn(4) with bhnd(4), place the following lines in loader.conf(5):

hw.bwn_pci.preferred="1"

if_bwn_pci_load="YES
bwn_v4_ucode_load="YES"
bwn_v4_lp_ucode_load="YES"

To verify that bwn(4) is using bhnd(4), you can check dmesg:

bwn0: <Broadcom 802.11 MAC/PHY/Radio, rev 15> ... on bhnd0

... or devinfo(8):

pcib2
pci2
bwn_pci0
bhndb0
bhnd0
bwn0
...

bwn(4)/bhnd(4) has been tested for regressions with most chipsets currently
supported by bwn(4), including:

- BCM4312
- BCM4318
- BCM4321

With minimal changes to the DMA code (not included in this commit), I was
also able to test support for newer BCMA devices by bringing up basic
working Wi-Fi on two previously unsupported, BCMA-based N-PHY chipsets:

- BCM43224
- BCM43225

Approved by: adrian (mentor, implicit)
Sponsored by: The FreeBSD Foundation & Plausible Labs
Differential Revision: https://reviews.freebsd.org/D13041

[bwn] add opt_wlan.h and opt_bwn.h to each of the phy_n source files.

[bwn] add initial bwn(4) N-PHY code, ported from Linux b43.

This is a GPLv2 PHY-N implementation based on the Linux b43 driver,
ported over to work in bwn(4).

I've tested this on the BCM4321 11abgn device, in 11bg and 11a modes.
The b43 PHY code only supports 11abg, no 11n, and 20MHz only wide
channels.

Yes, this is a GPLv2 driver, so it won't be included in the
default builds.

Tested:

* BCM4321 11abgn device (Apple!), 11bg and 11a STA mode.

Obtained from: Linux b43