drm: bridge: dw-hdmi: Pass drm_display_info to .mode_valid()

Replace the drm_connector pointer passed to the .mode_valid() function
with a const drm_display_info pointer, as that's all the function should
need. Use the display info passed to the bridge .mode_valid() operation
instead of retrieving it from the connector, to prepare for make
connector creation optional.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200526011505.31884-16-laurent.pinchart+renesas@ideasonboard.com