powerpc/p1022ds: fix rtc compatible string

RTC Hardware(ds3232) and rtc compatible string does not match.
Change "dallas,ds1339" to "dallas,ds3232".
Signed-off-by: NWang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

arch/powerpc/boot/dts/p1022ds.dtsi

@@ -146,7 +146,7 @@
 			 */
 		};
 		rtc@68 {
-			compatible = "dallas,ds1339";
+			compatible = "dallas,ds3232";
 			reg = <0x68>;
 		};
 		adt7461@4c {