bluetooth: mesh: avoid improper access to internal structures

Nothing in the API description the delayed work structure sanctions
direct reference to internal fields.  Do not assume that a delayed
work item can be submitted without delay by invoking k_work_submit()
with a reference to the contained work item.  Instead submit with the
delayed API and no wait.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2 files changed