Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Use proper kern.opts.mk rather than src.opts.mk from r297058.

Reported by: kib
Sponsored by: EMC / Isilon Storage Division

[urtwn] migrate urtwn out into sys/dev/urtwn/ .

There's some upcoming work to add new chipset support here and I'd
like to only add 802.11n support to one driver, instead of both
urtwn and rtwn.

There's also missing support for things like 802.11n, some powersave
work, bluetooth integration/coexistence, etc, and also newer parts
(like 8192EU, maybe some 11ac parts, not sure yet.)

So, this is hopefully the first step in a longer set of steps to unify
rtwn/urtwn and extend it with more interesting chipset and functionality
support.

Reviewed by: kevlo

urtwn: add an option to compile the driver without firmware specific code

- Add URTWN_WITHOUT_UCODE option (will disable any firmware specific code
when set).
- Do not exclude the driver from build when MK_SOURCELESS_UCODE is set
(URTWN_WITHOUT_UCODE will be enforced unconditionally).
- Do not abort initialization when firmware cannot be loaded;
behave like the URTWN_WITHOUT_UCODE option was set.
- Drop some unused variables from urtwn_softc structure.

Tested with RTL8188EU and RTL8188CUS in HOSTAP and STA modes.

Reviewed by: kevlo
Approved by: adrian (mentor)
Differential Revision: https://reviews.freebsd.org/D4849

urtwn(4): split *reg and *var parts (no functional change).

Submitted by: <s3erios@gmail.com>
Differential Revision: https://reviews.freebsd.org/D3775

Add opt_wlan.h as requirements for the two drivers I'm currently working on.

Import Kevin Lo's port of urtwn(4) from OpenBSD. urtwn(4) is a driver for the
Realtek RTL8188CU/RTL8192CU USB IEEE 802.11b/g/n wireless cards.
This driver requires microcode which is available in FreeBSD ports:
net/urtwn-firmware-kmod.

Hiren ported the urtwn(4) man page from OpenBSD and Glen just commited a port
for the firmware.

TODO:
- 802.11n support
- Stability fixes - the driver can sustain lots of traffic but has trouble
coping with simultaneous iperf sessions.
- fix debugging

MFC after: 2 months
Tested by: kevlo, hiren, gjb