drm/i915: Remove one use macro

Remove one use macro for_each_connector_on_encoder which
is only being used at intel_encoder_find_connector.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221020104635.874860-2-suraj.kandpal@intel.com