include: zephyr: dt-bindings: comparator: silabs: generate acmp

Generates bindings that define acmp inputs. These bindings can be
used in devicetree sources to configure the acmp's
input-positive and input-negative properties. Depending on the
part, some inputs may not be available as positive and/or
negative inputs to the ACMP, therefore always reference your
part's design book when selecting these inputs.

Signed-off-by: Christian Galante <christian.galante@silabs.com>