bring_all_ap_online() now initialises all APs in parallel, and waits for them all to come online (i.e. reach the end of ap_trampoline_exit, making them ready to start scheduling threads) before returning.
bring_all_ap_online() now initialises all APs in parallel, and waits for them all to come online (i.e. reach the end of ap_trampoline_exit, making them ready to start scheduling threads) before returning.