drm/bridge: dw-hdmi: Remove the legacy drm_connector_funcs structure

There is no one using the legacy drm_connector_funcs structure since
the imx-drm has been converted to atomic, so we may remove it.

Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>