drm/bridge: tfp410: Support format negotiation hooks

With new connector model, tfp410 will not create the connector and
SoC driver will rely on format negotiation to setup the encoder format.

Support format negotiations hooks in the drm_bridge_funcs.
Use helper functions for state management.

Input format is the one selected by the bridge from DT properties.

Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
[a-bhatia1: Removed output fmt condition check]
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606082142.23760-2-a-bhatia1@ti.com