Revert "ondemandplus governor: remove adaptive timer_rate logic"

This reverts commit 47ddf89a24a113b359cf9391e3e1849a5fb3102f.
Revert "ondemandplus: add and enable io_is_busy=2 option, adjust up_threshold and down_differential"

This reverts commit b60a217b5aedc5a637c2544aeffc60637c8c5826.
revert: add ondemandplus governor