Docs: Mention device tree binding info

Suggested-by: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/SubmittingPatches

@@ -15,7 +15,8 @@ format.  For detailed information on how the kernel development process
 works, see Documentation/development-process.  Also, read
 Documentation/SubmitChecklist for a list of items to check before
 submitting code.  If you are submitting a driver, also read
-Documentation/SubmittingDrivers.
+Documentation/SubmittingDrivers; for device tree binding patches, read
+Documentation/devicetree/bindings/submitting-patches.txt.
 
 Many of these steps describe the default behavior of the git version
 control system; if you use git to prepare your patches, you'll find much