can: ifi: Add DT bindings for ifi,canfd

Add device tree bindings for the I/F/I CANFD controller IP core.

Signed-off-by: Marek Vasut <[e-mail]>
Cc: Marc Kleine-Budde <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Oliver Hartkopp <[e-mail]>
Cc: Wolfgang Grandegger <[e-mail]>
Signed-off-by: Marc Kleine-Budde <[e-mail]>

Documentation/devicetree/bindings/net/can/ifi_canfd.txt

···
+IFI CANFD controller
+--------------------
+
+Required properties:
+  - compatible: Should be "ifi,canfd-1.0"
+  - reg: Should contain CAN controller registers location and length
+  - interrupts: Should contain IRQ line for the CAN controller
+
+Example:
+
+	canfd0: canfd@ff220000 {
+		compatible = "ifi,canfd-1.0";
+		reg = <0xff220000 0x00001000>;
+		interrupts = <0 43 0>;
+	};