dt-bindings: input: goodix,gt9916: Document gt9897 compatible

Document the Goodix GT9897 which is a Berlin-A series touchscreen
controller IC by Goodix.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Jens Reidel <adrian@mainlining.org>
Link: https://lore.kernel.org/r/20250309062315.35720-2-adrian@mainlining.org


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