[PATCH v3] of: Create asm-generic/of.h and provide default of_node_to_nid()

[David Miller]

From: Grant Likely <grant.likely at secretlab.ca>
Date: Mon, 26 Jul 2010 16:42:20 -0600

> It protects against some later include file doing a #define
> of_node_to_nid and thus resulting in an inconsistent definition.  If
> some code tries to do this then the preprocessor will complain.  This
> is the pattern that Stephen suggested.

Also, it would be nice to unravel the "0" vs. "-1" default
inconsistency.