dt-bindings: input: touchscreen: convert colibri-vf50-ts.txt to yaml

Convert binding doc colibri-vf50-ts.txt to yaml.
Additional change:
- add ref touchscreen.yaml.
- remove standard pinctrl properties.

Fix below warning:
arch/arm64/boot/dts/freescale/imx8qm-apalis-eval.dtb: /touchscreen:
  failed to match any schema with compatible: ['toradex,vf50-touchscreen']

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240819142434.311760-1-Frank.Li@nxp.com


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