Currently, cma users can't increase or decrease the cma reference
count. This is necassary when setting cma attributes (like the
default GID type) in order to avoid use-after-free errors.
Adding cma_ref_dev and cma_deref_dev APIs.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>