drm: Match drm_dp_send_clear_payload_id_table definition to declaration

drivers/gpu/drm/drm_dp_mst_topology.c:2898:6: warning: symbol 'drm_dp_send_clear_payload_id_table' was not declared. Should it be static?
drivers/gpu/drm/drm_dp_mst_topology.c:5451:37: warning: missing braces around initializer
drivers/gpu/drm/drm_dp_mst_topology.c:5451:37: warning: missing braces around initializer

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200516212330.13633-4-chris@chris-wilson.co.uk