- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Initial AR9485/AR933x 1x1 LNA diversity work.

* Add the LNA configuration table entries for AR933x/AR9485
* Add a chip-dependent LNA signal level delta in the startup path
* Add a TODO list for the stuff I haven't yet ported over but
I haven't.

Tested:

* AR9462 with LNA diversity enabled

Migrate the LNA mixing diversity machinery from the AR9285 HAL to the driver.

The AR9485 chip and AR933x SoC both implement LNA diversity.
There are a few extra things that need to happen before this can be
flipped on for those chips (mostly to do with setting up the different
bias values and LNA1/LNA2 RSSI differences) but the first stage is
putting this code into the driver layer so it can be reused.

This has the added benefit of making it easier to expose configuration
options and diagnostic information via the ioctl API. That's not yet
being done but it sure would be nice to do so.

Tested:

* AR9285, with LNA diversity enabled
* AR9285, with LNA diversity disabled in EEPROM