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

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

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

rtwn_usb(4): fix LED blinking for RTL8192CU during scanning

Tested with RTL8188CUS, STA mode.

MFC after: 5 days

Add support for the Realtek RTL8192EU chipset.
Committed over the D-Link DWA-131 rev E1 on amd64 with WPA.

Reviewed by: avos

In rtl8188eu, read R92C_HSSI_PARAM2(0)) register to detect whether it needs
to enable CCK high power feature or not.

Reviewed by: avos

Merge r92c_init_rf_common() into r92c_init_rf(). In r88eu_attach.c, we could
use r92c_init_rf() rather than r92c_init_rf_common() when sc_init_rf()
callback is invoked.

While here, constantly use RF chain instead of RF path in comment.

Reviewed by: avos

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