Devicetree Specification prerelease v0.2-pre2

Hi everyone,

Quick note to say progress is being made on the devicetree
specification again. We've just tagged v0.2-pre2 in preparation for a
v0.2 release before the end of the 2017. You can find the new release
pdf here:

https://github.com/devicetree-org/devicetree-specification/releases

Most of the changes are cosmetic, but there are a few content changes.
You can expect a lot more content changes to go in the v0.3 sometime
early 2018.

7f8e2bd Add more recommended generic node names
ef302c9 Describe interrupts-extended property
4fac2e2 Document additional "phy-connection-type" values
418a599 Add items to Devicetree Source Format chapter

Please take a look and comment. Also, anyone wanting to help improve
the document can find the source here:

https://github.com/devicetree-org/devicetree-specification

g.