dt/bindings: submitting patches and ABI documents

Add some guidance documentation about what to do with device tree
bindings and how ABI stability is to be handled.

Signed-off-by: Jason Cooper <jason@lakedaemon.net>
[grant.likely: added some clarification on subsystem binding rules]
Signed-off-by: Grant Likely <grant.likely@linaro.org>
2 files changed