- 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

Implement some initial AR934x support routines.

This code reads the PLL configuration registers and correctly programs
things so the UART and such can come up.

There's MIPS74k platform issues that need fixing; but this at least brings
things up enough to echo stuff out the serial port and allow for interactive
debugging with ddb.

Tested:

* AR71xx SoCs
* AR933x SoC
* AR9344 board (DB120)

Obtained from: Qualcomm Atheros; Linux/OpenWRT