dt-bindings: mmc: jz4740: Add bindings for X1000

Add the MMC bindings for the X1000 Soc from Ingenic.
Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/jz4740.txt

-* Ingenic JZ47xx MMC controllers
+* Ingenic XBurst MMC controllers
 
 This file documents the device tree properties used for the MMC controller in
-Ingenic JZ4740/JZ4780 SoCs. These are in addition to the core MMC properties
-described in mmc.txt.
+Ingenic JZ4740/JZ4760/JZ4780/X1000 SoCs. These are in addition to the core MMC
+properties described in mmc.txt.
 
 Required properties:
 - compatible: Should be one of the following:
@@ -10,6 +10,7 @@ Required properties:
   - "ingenic,jz4725b-mmc" for the JZ4725B
   - "ingenic,jz4760-mmc" for the JZ4760
   - "ingenic,jz4780-mmc" for the JZ4780
+  - "ingenic,x1000-mmc" for the X1000
 - reg: Should contain the MMC controller registers location and length.
 - interrupts: Should contain the interrupt specifier of the MMC controller.
 - clocks: Clock for the MMC controller.