cpufreq_ondemand.c: rework touch and introduce boost

- restructure
- simplify a bit (remove timer_delay)
- rename to boost
- boost:
_ if a cpu is at max, boost available to help
_ if touch, boost available to help
_ we add boost_percent if cpu is boosted and load is at or above
lower_threshold (to help when cpu is actually in use) and at or below
upper_threshold (to not boost too high)

Signed-off-by: SkipXS <sskkiipp@gmail.com>