[dtc] Add support for flat device tree format version 17

[Jon Loeliger]

So, like, the other day David Gibson mumbled:
> libfdt defined a new version of the flattened device tree format,
> version 17.  It is backwards compatible with version 16, just adding
> an extra header field giving the size of the blob's structure blob.
> 
> This patch adds support to dtc allowing it to read and write version
> 17 blobs.  It also makes version 17 the default output version for
> blobs.
> 
> At the same time we change the code to consistently using decimal
> numbers for versions.  Previously we sometimes used 16 and sometimes
> 0x10 to refer to version 16.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

Thanks,
jdl