Documentation: Extend release checklist (list to-be deprecated boards)

Make it part of the release process to note not only what config flags /
code properties etc will be deprecated, but to also spell out which
boards would be affected at the time of the release.

Change-Id: I0ef1404e75182ea4bacae31edb0a843e7a359545
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37702
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

Documentation/releases/checklist.md

@@ -56,6 +56,9 @@ be more frequent than was needed, so we scaled it back to twice a year.
       and to update the release notes
 - [ ] Update the topic in the irc channel with the date of the upcoming
       release
+- [ ] If there are any deprecations announced for the following release,
+      make sure that a list of currently affected board and chipsets is
+      part of the release notes.
 - [ ] Finalize release notes (as much as possible), without specifying
       release commit ids