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

Import the initial CPU support for the MIPS RALink RT305x SoC.
This is a MIPS4KC CPU with various embedded peripherals, including
wireless and ethernet support.

This commit includes the platform, UART, ethernet MAC and GPIO support.
The interrupt-driven GPIO code is disabled for now pending GPIO changes
from the submitter.

Submitted by: Aleksandr Rybalko <ray@dlink.ua>