adding OF_DYNAMIC proc interface - 2nd try

[atull at altera.com]

Hello,

(Fixed my mail configuration from earlier).

The following patch adds a /proc/ofdt interface to add or remove device tree
nodes dynamically.

Based on earlier feedback, I've changed my driver to use /proc instead of
creating a new ioctl (the old thread is at 
http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg17333.html)

I was hoping to get some early feedback from others who might be interested
who were discussing this on an earlier thread about OF_DYNAMIC usage.

This code doesn't do any notification for drivers yet. It can add multiple
nodes and they will show up properly under /proc/device-tree.  It has an
issue that shows up when removing nodes (it appears that the memory used by
proc gets corrupted after the add).

Alan Tull
Altera