dt-bindings: i2c: mv64xxx: Fix the example compatible

One example has a compatible that isn't a valid combination according to
the binding, and now that the examples are validated as well, this
generates a warning.

Let's fix this.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>