hotplug: add correct dependency

For now this driver really needs this dependency to
work properly.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
hotplug: make dedicated workqueue freezeable

This makes the logic a bit more simpler to understand
and read. Apart from the higher initial startup delay
it shouldnt touch any functionality.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>