tests: Add check_path test

Add a test that checks for existence or not of a node.
It is useful for testing the various cases when generating
symbols and fixups for dynamic device tree objects.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
4 files changed