Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Update the AR9280v2 inivals to match what is in Linux ath9k.

This repairs the behaviour of my AR9280 - both radio chains now seem
to correctly be receiving.

Push the non-AR5416 related stuff into chipset specific directories.

sys/dev/ath/ath_hal/ar5416/ is getting very crowded and further
commits will make it even more crowded. Now is a good time to
shuffle these files out before any more extensive work is done
on them.

Create an ar9003 directory whilst I'm here; ar9003 specific
chipset code will eventually live there.

preliminary ar9280 support:
o add 9280 attach that sets up ini, cal, etc.
o new rf backend for 9280 and later parts
o split ini setup and spur mitigation support out to methods
and provide 9280-specific support
o minor fixups to shared code to handle 9280-specific work

Obtained from: Atheros (ini values and some code)