Revert "softirq: use ffs() in __do_softirq()"

This reverts commit dbece3e746f95a6fc01711aa9accffc312ddd3c0.
Revert "sched: Introduce preempt_count accessor functions"

This reverts commit d0e4b2ef12dbc679ea3a185990816b060c2a3001.
Revert "irq: Optimize softirq stack selection in irq exit"

This reverts commit 23754855d5b152ca47574f7e3d031336375907a3.
Revert "irq: Justify the various softirq stack choices"

This reverts commit 64b1ebfef361d7862dc88e701aed3c681a10d323.
Revert "irq: Improve a bit softirq debugging"

This reverts commit 725e6b14a94d2b507168462744f672f60ca78273.
Revert "irq: Optimize call to softirq on hardirq exit"

This reverts commit ce749920b61f272541fd992826578e3e82f2a5cc.
Revert "irq: Consolidate do_softirq() arch overriden implementations"

This reverts commit bfd6eba593781b54f27c869efb4fabd58e426758.
Revert "irq: Force hardirq exit's softirq processing on its own stack"

This reverts commit 9fb3ad2166a474dfefd4ae41c76f9e35593bd62a.
Revert "Fix lockup related to stop_machine being stuck in __do_softirq."

This reverts commit a4b779749cf4e70c416c4c6ea82615dac8f9744d.
Revert "irq: Don't re-enable interrupts at the end of irq_exit"

This reverts commit edd002ce03acdbab14c317b0ca7115e3a9e22e2a.
Revert "irq: Remove IRQ_EXIT_OFFSET workaround"

This reverts commit c68cd1841fac8444ada16c9b7fd016b97710fbb6.
Revert "irq: Sanitize invoke_softirq"

This reverts commit 096080eea118674d1a556f79a9cb69e05e1f08cf.
Revert "irq: Ensure irq_exit() code runs with interrupts disabled"

This reverts commit 512c28fd493213fb5d00cb165d4b8b1dd1d6c66d.
Revert "lpm_levels: Do not allow power collapse when multi cores online"

This reverts commit cb7e9bc1c9e27713981d9b1da1eb1b0e487a999d.