msm: hotplug: New capabilities and fixes

* Remove unused import
* Add enable/disable toggle for debugging purpose
* Handling down lock per cpu is more precise. We can now distinguish
  between a regular interval and a generous time online after the last
  input event, where it's likely that the user will interact with the
  UI within then next few seconds again.

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>