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

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

iwm(4): Remove _mvm from the namespace.

This was inherited from iwlwifi, which drives devices supported by both
iwn(4) and iwm(4) in FreeBSD. In iwm(4) _mvm is meaningless, so remove
it. OpenBSD made the same change a long time ago. No functional change
intended.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

[iwm] Allow listening on both chains/atennas to get diversity.

This might improve throughput slightly when far from the accesspoint,
apparently by allowing the firmware to listen on either of the two
antennas (if there are two, i.e. on 7260/7265/8260), whichever has
a better reception.

Obtained from: dragonflybsd.git 3b7fc5aac51f81062da0a2c8fdac23e683fbd548

[iwm] include opt_iwm.h and opt_wlan.h consistently in all files.

[iwm] Sync valid_tx_ant and valid_rx_ant mask handling with iwlwifi.

* This fixes the phy_cfg field sent in the iwm_send_phy_cfg_cmd()
command, which wasn't taking into account the valid_rx_ant and
valid_tx_ant masks from nvm_data before.

Tested:

* 7260, STA mode, 2G and 5G

Obtained from: DragonflyBSD commit cbb82693c18fd71b4eb86855b82d03995f352d65

iwm(4) synchronize driver to DragonFlyBSD version and recent f/w update.

Submitted by: Kevin Bowling (kevin.bowling@kev009.com)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D6967

iwm: add 'opt_wlan.h' include into source files.

Include net80211 options file, so IEEE80211_DEBUG_REFCNT option will be
handled correctly.

Replay r286410. Change KPI of how device drivers that provide wireless
connectivity interact with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
driver about any changes: number of wlan(4) interfaces, number of them
in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
driver experiences errors and can not attribute them to any specific
interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to pluknet@, Oliver Hartmann,
Olivier Cochard, gjb@, mmoll@, op@ and lev@, who also participated in
testing.

Reviewed by: adrian
Sponsored by: Netflix
Sponsored by: Nginx, Inc.

iwm: use the proper include path for iwm headers.

Import OpenBSD's iwm WiFi driver for Intel 3160/7260/7265.

There are still several bugs, but I've been using it for a while now.
Thanks to all the testers and to Adrian for his help with this
driver.

This driver isn't connected to the build yet, but it will be soon.

There's no MFC planned because the driver isn't very stable yet.

Reviewed by: adrian
Obtained from: https://github.com/rpaulo/iwm
Tested by: adrian, gjb, dumbbell (others that I forgot).
Relnotes: yes