Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
Update all files possible under sched/timer to Apache 2.0. These excludes two files that have a Xiaomi copyright. Also, run all modified files through nxstyle to assure that the conform to the coding standard.
