drm/i915/irq: clarify irq storm related function naming

We'll have three functions:

intel_hpd_irq_storm_detect for detecting irq storms,
intel_hpd_irq_storm_disable for disabling hotplugs after detected storms,
intel_hpd_irq_storm_reenable_work for re-enabling hotplug.

No functional changes.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>