drm: Remove drm dp mst destroy_connector callbacks

drm: Remove drm dp mst destroy_connector callbacks

drm_dp_mst_topology_mgr_cbs.destroy_connector callbacks are identical
amongst every driver and don't do anything other than cleaning up the
connector((drm_connector_unregister()/drm_connector_put())) except for
amdgpu_dm driver where some amdgpu_dm specific code in there.

This connector cleaning up is now being handled in the drm core so
driver destroy_connector callbacks are not needed (except for
amdgpu_dm) hence remove them.

Removal is done with below sementic patch:

@r1@
identifier func, E;
@@
struct drm_dp_mst_topology_cbs E = {
	...,
-        .destroy_connector = func
};

@delete depends on r1@
identifier r1.func;
@@
- static void func(...){...}

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Suggested-by: Emil Velikov <emil.velikov@collabora.com>
Suggested-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200307083023.76498-6-pankaj.laxminarayan.bharadiya@intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>