drm: bridge: dw-hdmi: Pass drm_connector to internal functions as needed

To prepare for making connector creation optional in the driver, pass
the drm_connector explicitly to the internal functions that require it.
The functions that still access the connector from the dw_hdmi structure
are dw_hdmi_connector_create() and __dw_hdmi_probe(). The former access
is expected, as that's where the internal connector is created. The
latter will be addressed separately.

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/20200526011505.31884-22-laurent.pinchart+renesas@ideasonboard.com