src/mb: Add SPDX identifiers to files missing them
This adds SPDX identifiers to the remaining source files in the
mainboard directory that don't already have them.
Change-Id: I1adc204624f3ab6fcafd8fbb239e6d69e057973a
Signed-off-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66498
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>