dt-bindings: ps2-gpio: convert binding to json-schema

Changes since v1
================
  - binding as separate patch (driver patch will be sent outside the scope of
    this patch series)
  - fixes requested by Krzysztof
  - fix warnings/errors reported by 'make dt_binding_check'

This series converts the ps2-gpio dt-binding to the json-schema.

Additionally, it documents to flag the given gpios as open drain, since the
PS/2 bus is open drain by definition.

Danilo Krummrich (2):
      dt-bindings: ps2-gpio: convert binding to json-schema
      dt-bindings: ps2-gpio: document bus signals open drain

 Documentation/devicetree/bindings/serio/ps2-gpio.txt  | 23 -----------------------
 Documentation/devicetree/bindings/serio/ps2-gpio.yaml | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 23 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/serio/ps2-gpio.txt
 create mode 100644 Documentation/devicetree/bindings/serio/ps2-gpio.yaml