powerpc: doc/dts-bindings: update doc of FSL I2C bindings

This patch adds the MPC5121 to the list of supported devices,
enhances the doc of the "clock-frequency" property and removes
the obsolete "cell-index", "device_type" and "fsl-i2c" property.
Furthermore an example for the MPC5121 has been added.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

Documentation/powerpc/dts-bindings/fsl/i2c.txt

@@ -2,15 +2,14 @@
 
 Required properties :
 
- - device_type : Should be "i2c"
  - reg : Offset and length of the register set for the device
+ - compatible : should be "fsl,CHIP-i2c" where CHIP is the name of a
+   compatible processor, e.g. mpc8313, mpc8543, mpc8544, mpc5121,
+   mpc5200 or mpc5200b. For the mpc5121, an additional node
+   "fsl,mpc5121-i2c-ctrl" is required as shown in the example below.
 
 Recommended properties :
 
- - compatible : compatibility list with 2 entries, the first should
-   be "fsl,CHIP-i2c" where CHIP is the name of a compatible processor,
-   e.g. mpc8313, mpc8543, mpc8544, mpc5200 or mpc5200b. The second one
-   should be "fsl-i2c".
  - interrupts : <a b> where a is the interrupt number and b is a
    field that represents an encoding of the sense and level
    information for the interrupt.  This should be encoded based on
@@ -24,25 +23,40 @@ Recommended properties :
 
 Examples :
 
+	/* MPC5121 based board */
+	i2c@1740 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "fsl,mpc5121-i2c", "fsl-i2c";
+		reg = <0x1740 0x20>;
+		interrupts = <11 0x8>;
+		interrupt-parent = <&ipic>;
+		clock-frequency = <100000>;
+	};
+
+	i2ccontrol@1760 {
+		compatible = "fsl,mpc5121-i2c-ctrl";
+		reg = <0x1760 0x8>;
+	};
+
+	/* MPC5200B based board */
 	i2c@3d00 {
 		#address-cells = <1>;
 		#size-cells = <0>;
 		compatible = "fsl,mpc5200b-i2c","fsl,mpc5200-i2c","fsl-i2c";
-		cell-index = <0>;
 		reg = <0x3d00 0x40>;
 		interrupts = <2 15 0>;
 		interrupt-parent = <&mpc5200_pic>;
 		fsl,preserve-clocking;
 	};
 
+	/* MPC8544 base board */
 	i2c@3100 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		cell-index = <1>;
 		compatible = "fsl,mpc8544-i2c", "fsl-i2c";
 		reg = <0x3100 0x100>;
 		interrupts = <43 2>;
 		interrupt-parent = <&mpic>;
 		clock-frequency = <400000>;
 	};
-