Contrary to the documentation giving a semaphore while an IRQ lock is
held does not release the lock and give control to another thread.
The release-lock behavior is observed only if the lock-holding thread
sleeps.
However the opportunity to reschedule will have been lost so it may be
necessary to explicitly yield to allow the higher-priority thread to
be serviced.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
c42eb823ce