drm/vc4: hdmi: Update all the planes if the TV margins are changed

On VC4, the TV margins on the HDMI connector are implemented by scaling
the planes.

However, if only the TV margins or the connector are changed by a new
state, the planes ending up on that connector won't be. Thus, they won't
be updated properly and we'll effectively ignore that change until the
next commit affecting these planes.

Let's make sure to add all the planes attached to the connector so that
we can update them properly.

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20221207-rpi-hdmi-improvements-v3-2-bdd54f66884e@cerno.tech


Signed-off-by: Maxime Ripard <maxime@cerno.tech>