ARM: dts: pxa: add pwri2c to pxa device-tree

pxa27x variant has 2 I2C busses on the SoC :
 - the casual I2C
 - the power I2C, normally driving power regulators, and capable of
 receiving orders on core frequency modifications

Add the missing pwri2c to pxa27x description.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>

arch/arm/boot/dts/pxa27x.dtsi

@@ -35,6 +35,13 @@ pwm3: pwm@40c00010 {
 			reg = <0x40c00010 0x10>;
 			#pwm-cells = <1>;
 		};
+
+		pwri2c: i2c@40f000180 {
+			compatible = "mrvl,pxa-i2c";
+			reg = <0x40f00180 0x24>;
+			interrupts = <6>;
+			status = "disabled";
+		};
 	};
 
 	clocks {