Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Initial device tree source (DTS) files for Marvell ARM systems:

o DB-88F5182
o DB-88F5281
o DB-88F6281
o DB-78100
o SheevaPlug

This also includes device tree bindings definitions for some newly introduced
nodes (mpp, gpio).

Reviewed by: imp
Sponsored by: The FreeBSD Foundation