(split) Add missing libexec/bsdconfig subdirectories
(split) Fixes for the RSU driver:
- The R92S_TCR register is an 8-bit register. Don't access it like a
16-bit register.
- Disable parsing the delete station event, due to many false events.
- Ensure that there is only one transfer queue for each endpoint, so
that packets transmitted don't get out of order.

MFC after:	1 week
(split) More RSU fixes:
- Properly align temporary buffer to 32-bit.
- Add an extra parenthesis to make expression clear.
- Range check the association ID received from hardware.

MFC after:	1 week
(split) Remove D-Link DWA140 rev D1 by accident.

Pointed out by Anders Larsson in private email.
(split) Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies
(split) Revert r267961, r267973:

These changes prevent sysctl(8) from returning proper output,
such as:

 1) no output from sysctl(8)
 2) erroneously returning ENOMEM with tools like truss(1)
    or uname(1)
 truss: can not get etype: Cannot allocate memory
(split) Pull in r267961 and r267973 again. Fix for issues reported will follow.
(split) Merge branch 'CURRENT' (commit '4618d6ea')