powerpc: dts: Fix some I2C unit addresses

The unit-address for the Maxim MAX1237 ADCs on XPedite5200 boards don't
match the value in the "reg" property and cause a DTC warning.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211220134036.683309-1-thierry.reding@gmail.com

arch/powerpc/boot/dts/xpedite5200.dts

@@ -132,7 +132,7 @@ rtc@68 {
 				reg = <0x68>;
 			};
 
-			dtt@48 {
+			dtt@34 {
 				compatible = "maxim,max1237";
 				reg = <0x34>;
 			};

arch/powerpc/boot/dts/xpedite5200_xmon.dts

@@ -136,7 +136,7 @@ rtc@68 {
 				reg = <0x68>;
 			};
 
-			dtt@48 {
+			dtt@34 {
 				compatible = "maxim,max1237";
 				reg = <0x34>;
 			};