Because it's the function that destroys the connector, not the
encoder. And we already have intel_dp_encoder_destroy.

This has annoyed me for a long time.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NZoltan Nyul <zoltan.nyul@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>