powerpc: Remove device_type = "rtc" properties in .dts files

We don't want to encourage the device_type usage.  It isn't used in
the code, so we can simply remove it from the dts files.

Suggested-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/boot/dts/kuroboxHD.dts

@@ -76,7 +76,6 @@ XXXX add flash parts, rtc, ??
 			interrupt-parent = <&mpic>;
 
 			rtc@32 {
-				device_type = "rtc";
 				compatible = "ricoh,rs5c372a";
 				reg = <0x32>;
 			};