Update details for upcoming 4.15 release Signed-off-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com> Change-Id: I4517f7c17ce5788c82a1eafb1589e39b1ce403ff Reviewed-on: https://review.coreboot.org/c/coreboot/+/58422 Reviewed-by: Martin Roth <martinroth@google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>