Dt-bindings: Serial: Add X1000 serial bindings.

Add the serial bindings for the X1000 Soc from Ingenic.
Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/ingenic,uart.txt

@@ -6,7 +6,8 @@ Required properties:
   - "ingenic,jz4760-uart",
   - "ingenic,jz4770-uart",
   - "ingenic,jz4775-uart",
-  - "ingenic,jz4780-uart".
+  - "ingenic,jz4780-uart",
+  - "ingenic,x1000-uart".
 - reg : offset and length of the register set for the device.
 - interrupts : should contain uart interrupt.
 - clocks : phandles to the module & baud clocks.