ARM: dts: imx27 phyCARD-S remove wrong I2C RTC

Fixup of commit "ARM: dts: Add device tree support for phycard pca100".

Remove wrong I2C RTC node.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx27-phytec-phycard-s-som.dts

@@ -55,11 +55,6 @@ lm75@4a {
 		reg = <0x4a>;
 	};
 
-	rtc@51 {
-		compatible = "nxp,pcf8563";
-		reg = <0x51>;
-	};
-
 	at24@52 {
 		compatible = "at,24c32";
 		pagesize = <32>;