dt-bindings: pinctrl: brcm: Ensure all child node properties are documented

dt-bindings: pinctrl: brcm: Ensure all child node properties are documented

The Broadcom pinctrl bindings are incomplete for child nodes as they are
missing 'unevaluatedProperties: false' to prevent unknown properties.
Fixing this reveals many warnings including having grandchild nodes in some
cases. Many cases in the examples use 'group' property which is
undocumented and not used by the driver. As the schemas define 'pins', I
assume that is the correct name except for the one case, 6358, using
'groups' which is documented.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231020185203.3941590-2-robh@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>