Revert "Widen EPOCH(9) usage in PCI WLAN drivers."

This reverts commit b65f813c1ab99448278961c5ca80dc422b1eae29.
As a side effect this also seems to fix wtap which seems to have
lost the epoch over the input path in between.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

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

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

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

Widen EPOCH(9) usage in PCI WLAN drivers.

Make sure all occurrences of ieee80211_input_xxx() in sys/dev are
covered by a network epoch section. Do not depend on the interrupt
handler nor any taskqueues being in a network epoch section.

This patch should unbreak the PCI WLAN drivers after r357004.

Pointy hat: glebius@
Sponsored by: Mellanox Technologies

rtwn_pci(4): fix panic with INVARIANTS (due to inverted assertion logic)

MFC after: 4 days

rtwn_pci(4): add support for event-based Tx reports.

It will be used for RTL8188EE (and, probably, others).

MFC after: 4 days

rtwn_pci(4): use proper bus_dmamap_sync flags after Tx (sync with r342672)

MFC after: 4 days

rtwn: add Rx descriptor structures for common code.

Remove any chipset specific usage of Rx descriptor structure / bits
from common code to prevent misuse of fields that may differ
between various chipsets.

Checked with: RTL8821AU in STA mode.

rtwn: drop unneeded (after r315583) code.

Tested with RTL8188EU, HOSTAP mode + RTL8821AU, STA mode
(fast-frames / A-MSDU).

rtwn: export more stats to net80211

Setup more ieee80211_rx_stats fields for received frames:
- pktflags:
* IEEE80211_RX_F_FAIL_FCSCRC;
* IEEE80211_RX_F_AMPDU;
* IEEE80211_RX_F_AMPDU_MORE;
* IEEE80211_RX_F_SHORTGI;
- rate flags (CCK, OFDM, HT);
- width;
- phytype;
- rate;
- rx_tsf;
- rssi;
- nf;
- ieee, freq (RTL8188EU only, when ht40 support is disabled).

Tested with:
- RTL8188CE, RTL8188EU, RTL8821AU (STA / AP modes, i386)
- (by kevlo) RTL8188EU and RTL8812AU (amd64)

Reviewed by: adrian (previous version), kevlo
Differential Revision: https://reviews.freebsd.org/D9021

rtwn: enable 11n support for RTL8188CE.

- Increase Rx buffer size from MCLBYTES to MJUMPAGESIZE.
- Provide an additional defragmentation routine for frames larger
than MCLBYTES; that is required by A-MSDU / Atheros Fast-Frames
support to work with current Tx path implementation.

Enabled features list for RTL8188CE:
- Atheros Fast-Frames;
- A-MPDU (Tx / Rx);
- A-MSDU (Tx / Rx; 4k only);
- Short Guard Interval.

Tested with:
- RTL8188CE (STA+AP) + RTL8821AU (STA).
- RTL8188CE (STA) + RTL8188CUS (AP).

Relnotes: yes

rtwn_pci: omit tx_done() stage if device is not running.
rtwn_usb: drain USB transfers during device shutdown; this fixes possible
panic with 'options IEEE80211_SUPPORT_SUPERG' during device detach.

Tested with RTL8188CE, STA mode.

rtwn(4), urtwn(4): merge common code, add support for 11ac devices.

All devices:
- add support for rate adaptation via ieee80211_amrr(9);
- use short preamble for transmitted frames when needed;
- multi-bss support:
* for RTL8821AU: 2 VAPs at the same time;
* other: 1 any VAP + 1 sta VAP.
RTL8188CE:
- fix IQ calibration bug (reason of significant speed degradation);
- add h/w crypto acceleration support.
USB:
- A-MPDU Tx support;
- short GI support;
Other:
- add support for RTL8812AU / RTL8821AU chipsets
(a/b/g/n only; no ac yet);
- split merged code into subparts:
* bus glue (usb/*, pci/*, rtl*/usb/*, rtl*/pci/*)
* common (if_rtwn*)
* chip-specific (rtl*/*)
- various other bugfixes.

Due to code reorganization, module names / requirements were changed too:
urtwn urtwnfw -> rtwn rtwn_usb rtwnfw
rtwn rtwnfw -> rtwn rtwn_pci rtwnfw

Tested with RTL8188CE, RTL8188CUS, RTL8188EU and RTL8821AU.

Tested by: kevlo, garga,
Peter Garshtja <peter.garshtja@ambient-md.com>,
Kevin McAleavey <kevin.mcaleavey@knosproject.com>,
Ilias-Dimitrios Vrachnis <id@vrachnis.com>,
<otacilio.neto@bsd.com.br>
Relnotes: yes