dt-bindings: gpio: dwapb: Add ngpios property support

It's redundant to have a vendor-specific property describing a number of
GPIOS while there is a generic one. Let's mark the former one as
deprecated and define the "ngpios" property supported with constraints
of being within [1; 32] range.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200730152808.2955-2-Sergey.Semin@baikalelectronics.ruSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/snps,dw-apb-gpio.yaml

@@ -61,8 +61,14 @@ patternProperties:
       '#gpio-cells':
         const: 2
 
+      ngpios:
+        default: 32
+        minimum: 1
+        maximum: 32
+
       snps,nr-gpios:
         description: The number of GPIO pins exported by the port.
+        deprecated: true
         $ref: /schemas/types.yaml#/definitions/uint32
         default: 32
         minimum: 1