Revert "stop_machine: Mark per cpu stopper enabled early"

This reverts commit 62d40216c21d88adaeae65c24ad215002e4bffea.
Revert "stop_machine: Use smpboot threads"

This reverts commit 0b6a178721947787d1a8da8968a37f668f9a8463.
Revert "stop_machine: Store task reference in a separate per cpu variable"

This reverts commit 425d2d8229fabb078d005eb5900283b007dff927.
Revert "hotplug: Fix UP bug in smpboot hotplug code"

This reverts commit fa224e3351971f91bbc576d5980b5eef98399a48.
Revert "smpboot, idle: Fix comment mismatch over idle_threads_init()"

This reverts commit fef8eeac96427cd64547454a989e78937ac0a023.
Revert "smpboot, idle: Optimize calls to smp_processor_id() in idle_threads_init()"

This reverts commit 1b6e81346b04b45bfec938d645cb1b4cc35d30b5.
Revert "smp, idle: Allocate idle thread for each possible cpu during boot"

This reverts commit af1a9b1680ddeb4ccf2d942310bd11d0fad1fdbe.