drm/i915: Do not start connector polling if display is disabled

Currently we are starting connector polling if display is disabled
using disable_display module parameter. Polling is just returning
always "not connected" state. This can be optimized by not starting
polling at all.

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220610085429.52935-3-jouni.hogander@intel.com