dt-bindings: input: touchscreen: st,stmfts: convert to dtschema

Convert the ST-Microelectronics FingerTip touchscreen controller
bindings to DT schema.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230127202040.196411-1-krzysztof.kozlowski@linaro.org


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