drm/mst: Fix sphinx warnings in drm_dp_msg_connector register functions

drm/mst: Fix sphinx warnings in drm_dp_msg_connector register functions

Fixes the following warnings:

../drivers/gpu/drm/drm_dp_mst_topology.c:1593: warning: Excess function parameter 'drm_connector' description in 'drm_dp_mst_connector_late_register'
../drivers/gpu/drm/drm_dp_mst_topology.c:1613: warning: Excess function parameter 'drm_connector' description in 'drm_dp_mst_connector_early_unregister'
../drivers/gpu/drm/drm_dp_mst_topology.c:1594: warning: Function parameter or member 'connector' not described in 'drm_dp_mst_connector_late_register'
../drivers/gpu/drm/drm_dp_mst_topology.c:1614: warning: Function parameter or member 'connector' not described in 'drm_dp_mst_connector_early_unregister'

Fixes: 562836a269e3 ("drm/dp_mst: Enable registration of AUX devices for MST ports")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190726142057.224121-1-sean@poorly.run