api: cpumask: add missing documentation for odp_cpumask_t

Previously odp_cpumask_t was documented only in ABI header file.

Signed-off-by: Matias Elo <matias.elo@nokia.com>
Reviewed-by: Tuomas Taipale <tuomas.taipale@nokia.com>
Reviewed-by: Petri Savolainen <petri.savolainen@nokia.com>
2 files changed