dtc: Merge refs and labels into single "markers" list

[Jon Loeliger]

So, like, the other day David Gibson mumbled:
> Currently, every 'data' object, used to represent property values, has
> two lists of fixup structures - one for labels and one for references.
> Sometimes we want to look at them separately, but other times we need
> to consider both types of fixup.
> 
> I'm planning to implement string references, where a full path rather
> than a phandle is substituted into a property value.  Adding yet
> another list of fixups for that would start to get messy.  So, this
> patch merges the "refs" and "labels" lists into a single list of
> "markers", each of which has a type field indicating if it represents
> a label or a phandle reference.  String references or any other new
> type of in-data marker will then just need a new type value - merging
> data blocks and other common manipulations will just work.
> 
> While I was at it I made some cleanups to the handling of fixups which
> simplify things further.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

Thanks,
jdl