Revision 307529

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