Setting 'additionalProperties: false' is frequently omitted, but is
important in order to check that there aren't extra undocumented
properties in a binding.

Ideally, we'd just add this automatically and make this the default, but
there's some cases where it doesn't work. For example, if a common
schema is referenced, then properties in the common schema aren't part
of what's considered for 'additionalProperties'. Also, sometimes there
are bus specific properties such as 'spi-max-frequency' that go into
bus child nodes, but aren't defined in the child node's schema.

So let's stick with the json-schema defined default and add
'additionalProperties: false' where needed. This will be a continual
review comment and game of wack-a-mole.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Stephen Boyd <sboyd@kernel.org> # clock
Acked-by: Lee Jones <lee.jones@linaro.org>