- 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

Remove the AR9285 specific structure for LNA diversity and use the HAL.

The AR9300 HAL update included the LNA diversity configuration information
so it can be used in the AR9485 configuration code.

Disable diversity combining support until I can get a firm answer
from Atheros as to what/when this is supposed to be enabled.

Using the default RX fast diversity settings seems to help quite
a bit.

Whilst I'm here, change the prototype to return HAL_BOOL rather than int.

Add the initial AR9285 PHY glue for supporting antenna diversity.
This code isn't currently used anywhere; it's just linked into the build.