dt-bindings: i2c-gpio: Use 'deprecated' keyword on deprecated properties

The i2c-gpio binding is the only case of 'not: true' being used for a
deprecated property. Update it to use the json-schema 2019.09
'deprecated' keyword instead. Define the type too in order to keep the
meta-schema happy.

This will disable warnings for these properties until the dtschema tools
are updated to handle 'deprecated', but they are only used in a few at91
dts files.

Cc: Wolfram Sang <wolfram@the-dreams.de>
Cc: linux-i2c@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/i2c/i2c-gpio.yaml

@@ -52,15 +52,15 @@ properties:
     description: sda and scl gpio, alternative for {sda,scl}-gpios
 
   i2c-gpio,sda-open-drain:
-    # Generate a warning if present
-    not: true
+    type: boolean
+    deprecated: true
     description: this means that something outside of our control has put
       the GPIO line used for SDA into open drain mode, and that something is
       not the GPIO chip. It is essentially an inconsistency flag.
 
   i2c-gpio,scl-open-drain:
-    # Generate a warning if present
-    not: true
+    type: boolean
+    deprecated: true
     description: this means that something outside of our control has put the
       GPIO line used for SCL into open drain mode, and that something is not
       the GPIO chip. It is essentially an inconsistency flag.