[roll] Roll zircon 88ecb9b..ee3937b (5 commits)

ee3937b [pci] Add class codes to DDK headers
d53f606 [async] Make inheritance of async::Wait and async::Task public.
e668e95 [kernel][tests] Use fbl::atomic<> rather than 'volatile'
798454d [netsvc][devmgr] Add option to disable netboot advertisements
3d2f1c5 [kernel][tests] Use thread_sleep_relative() rather than thread_sleep()

Change-Id: I310f5048e3cd99f8f7db9671371023914700368e
1 file changed