dt-bindings: input: iqs7222: Add properties for Azoteq IQS7222D

Extend the common binding to include a new variant of the silicon,
which effectively replaces a pair of slider nodes with a trackpad
node comprising the same or similar properties.

As part of this change, the if/then/else schema have been updated
to identify properties that are not supported by the new device.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/ZKrpOdp+rM8gDekw@nixie71


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>