dt-bindings: media: ti,cal: Fix example

The OV5640 sensor used in the example doesn't follow the binding and
omits the regulators. Add some to make the example valid.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901091852.479202-27-maxime@cerno.tech
Signed-off-by: Rob Herring <robh@kernel.org>