travis: ignore spdx reports
travis: ignore spdx reports

Do not force red status for PRs due to SPDX missing (license must be there). We will
add better SPDX checks later (more work required to enable these for 3rd party code).

mbedmicro/mbed,mbedmicro/mbed,mbedmicro/mbed,mbedmicro/mbed,mbedmicro/mbed