dtc: Handle linux,phandle properties which self-reference

[Jon Loeliger]

> Currently, dtc will generate phandles for nodes which are referenced
> elsewhere in the tree.  phandles can also be explicitly assigned by
> defining the linux,phandle property.  However, there is no way,
> currently to tell dtc to generate a phandle for a node if it is not
> referenced elsewhere.  This is inconvenient when it's expected that
> later processing on the flat tree might add nodes which _will_
> the node in question.
> 
> One way one might attempt to do this is with the construct:
> 	mynode: mynode {
> 		linux,phandle = <&mynode>;
> 		/* ... */
> 	};
> Though it's a trifle odd, there's really only one sensible meaning
> which can be assigned to this construct: allocate a unique phandle to
> "mynode" and put that in its linux,phandle property (as always).
> 
> Currently, however, dtc will choke on this self-reference.  This patch
> corrects this, making the construct above give the expected results.
> It also ensures a more meaningful error message is given if you
> attempt to process the nonsensical construct:
> 	mynode: mynode {
> 		linux,phandle = <&someothernode>;
> 		/* ... */
> 	};
> 
> The 'references' testcase is extended to cover this case, as well.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

Thanks,
jdl