Clarify property set revision rules
Clarify property set revision rules

Property set revisions are intended to allow for new properties to be
added in order to extend the functionality of a device. To preserve
compatibility between platform firmware and operating systems,
properties cannot be removed or modified, nor can new properties be
added unless they are marked as optional, in subsequent property set
revisions.

Update the language in process_rules.txt to make that clear. Remove the
paragraphs about firmware and operating system requirements to use the
latest revision and fall back to previous revisions as it is no longer
relevant with the clarified language.

Signed-off-by: Darren Hart <38f9eaa30910c40b06f5a60020b1222f2a953801@infradead.org>

ahs3/dsd