commit f90cec631c ("limit amount of make jobs") in our fork added a
new environment variable check to all the genromap scripts to limit the
number of parallel jobs. Port this check onto the new projects added by
upstream in the latest merge.
The latest upstream changes added one project (bl602_demo_blemeshnode)
without a genromap. Add one by copying the provided genblenode script.
Also make the genromap executable for two other newly-added projects.
