drm/i915: Rename 'tmp_mask'

Replace this silly tmp_mask with hotplug_trigger/te_trigger
where appropriate.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201028213323.5423-16-ville.syrjala@linux.intel.com