drm/i915: Prefer intel_connector over drm_connector in hotplug code

Replace the drm_connector loops with intel_connector loops to
streamline the code.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200121171100.4370-2-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>