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

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

Some vendors store the mac addresses of arge(4) as a literal sring in the
form xx:xx:xx:xx:xx:xx complete with ":" characters taking of 18 bytes
instead of 6 integers. Expose a "readascii" tuneable to handle this case.

Remove restriction on eepromac assignement for the first dev instance only.

Add eepromac address for DIR-825 to hints file.

Add readascii hint for DIR-825

Reviewed by: adrian@

Adjust magic numbers to allow attachment of ath(4) modules.

The DIR-825 cal data is in an odd spot. I don't know why it's here.

(This works on my board because I wrote new caldata into this spot;
but this obviously won't work for stock DIR-825 units out there.)

oops, make cfg read-write.

This is an initial board configuration for the D-Link DIR-825 dual-band
802.11n router.

The flash layout defaults to a 1 MiB section for the kernel so I'm trying
very hard to squeeze a minimialistic (LZMA compressde) kernel image into
that.

I've verified that it boots through to single user mode fine.

Issues:

* USB doesn't yet work as a module - I need to add something else to the
USB AR71xx build before that will work.
* There's no switch PHY support - but for now it quite happily behaves
as a useful dumb switch out of the box. Phew.
* Since a previous flash attempt trashed my radio configuration block,
I haven't yet verified whether the wireless works correctly.
I'll test that out shortly (read: once I re-calibrate the board somehow.)

Thanks to ray@ and the zrouter project for doing some of the initial
hard work in figuring out how to bring this board up.