dt-bindings: I2C: Add X1000 bindings.

Add the I2C bindings for the X1000 Soc from Ingenic.
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-jz4780.txt

 * Ingenic JZ4780 I2C Bus controller
 
 Required properties:
-- compatible: should be "ingenic,jz4780-i2c"
+- compatible: should be one of the following:
+  - "ingenic,jz4780-i2c" for the JZ4780
+  - "ingenic,x1000-i2c" for the X1000
 - reg: Should contain the address & size of the I2C controller registers.
 - interrupts: Should specify the interrupt provided by parent.
 - clocks: Should contain a single clock specifier for the JZ4780 I2C clock.