dt-bindings: input: Add bindings for Azoteq IQS269A

This patch adds device tree bindings for the Azoteq IQS269A
capacitive touch controller.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1588352982-5117-1-git-send-email-jeff@labundy.com


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