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 extra debugging for non-SIBA devices.

This is a no-op at the present moment, but will eventually remind me
where the SIBA specific demons lie.

Tested:

* BCM4322, STA mode

[bwn] rename TGS low registers to be consistent with naming scheme.

[bwn] add opt_wlan.h and opt_bwn.h so we can enable bwn debugging as appropriate.

Tested:

* BCM4322, STA mode (11a)

Sponsored by: Palm Springs

[bwn] begin migrating PHY common routines into if_bwn_phy_common.[ch].

This isn't compiled in yet; so some code here duplicates what
is in the existing code. I'll migrate it all out in subsequent
commits.

Obtained from: b43 (definitions), bcm-v4 specifications website