dt-bindings: Fix erroneous 'additionalProperties'

There's several cases of json-schema 'additionalProperties' at the wrong
indentation level which has the effect of making them DT properties. This
is harmless, but let's fix them so a meta-schema check for this can be
added.

In all the cases, either the 'additionalProperties' was extra or doesn't
work because there's a $ref to more properties. In the latter case, we
can use 'unevaluatedProperties' instead.

Reported-by: Iskren Chernev <iskren.chernev@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Saravanan Sekar <sravanhome@gmail.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>