Some DSI controllers are missing a reference to the recently added
dsi-controller.yaml schema. Add it and we can drop the duplicate parts.

Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Robert Chiras <robert.chiras@nxp.com>
Cc: Philippe Cornu <philippe.cornu@st.com>
Cc: Yannick Fertre <yannick.fertre@st.com>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20201002225924.3513700-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>