coreinfo: Use SPDX license identifiers

- Remove copyright notices and add authors to AUTHORS
- Use SPDX license identifiers for all files
- Add coreinfo to the license header lint

Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Change-Id: Ib0c5328a4027849b1eda4f57141a898335230726
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45178
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

payloads/coreinfo/AUTHORS

@@ -0,0 +1,14 @@
+# This is the list of coreinfo authors for copyright purposes.
+#
+# This does not necessarily list everyone who has contributed code, since in
+# some cases, their employer may be the copyright holder.  To see the full list
+# of contributors, and their email addresses, see the revision history in source
+# control.
+# Run the below commands in the coreinfo repo for additional information.
+# To see a list of contributors: git log --pretty=format:%an | sort | uniq
+# For patches adding or removing a name: git log -i -S "NAME" --source --all
+
+Advanced Micro Devices, Inc.
+Dave Jones
+Jordan Crouse
+Uwe Hermann