kernel/poll: Spinlockify

Poll gets a single subsystem lock for now.  The existing locking in
Ben's code is subtle, being used both for latency control and for
critical section protection.  So getting each k_poll_event to use a
separate lock will require care and a little logic change.  Do the
simple version for now, which still works to decouple it from the
global lock.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
1 file changed