dt-bindings: can-controller: add support for termination-gpios

Some boards provide GPIO controllable termination resistor. Provide
binding to make use of it.

Link: https://lore.kernel.org/r/20210818071232.20585-2-o.rempel@pengutronix.deSigned-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/can-controller.yaml

@@ -13,6 +13,15 @@ properties:
   $nodename:
     pattern: "^can(@.*)?$"
 
+  termination-gpios:
+    description: GPIO pin to enable CAN bus termination.
+    maxItems: 1
+
+  termination-ohms:
+    description: The resistance value of the CAN bus termination resistor.
+    minimum: 1
+    maximum: 65535
+
 additionalProperties: true
 
 ...