drm/tinydrm/repaper: Don't use tinydrm_display_pipe_init()

tinydrm.ko is going away so let's implement a connector.

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-10-noralf@tronnes.org