of: add consistency check to of_node_release()

Add an additional consistency check to of_node_release(), which is
called when the reference count of a devicetree node is decremented
to zero.  The node's children should have been deleted before the
node is deleted so check that no children exist.

Signed-off-by: Frank Rowand <frowand.list@gmail.com>
Link: https://lore.kernel.org/r/20230213185702.395776-7-frowand.list@gmail.com


Signed-off-by: Rob Herring <robh@kernel.org>