lantiq: fix DGN3500 root device

Signed-off-by: Daniel Gimpelevich <[email protected]>

SVN-Revision: 44428

target/linux/lantiq/dts/DGN3500.dtsi

@@ -2,7 +2,7 @@
 
 / {
 	chosen {
-		bootargs-append = "root=/dev/mtdblock5 console=ttyLTQ0,115200";
+		bootargs-append = "root= console=ttyLTQ0,115200";
 	};
 
 	memory@0 {