Ok, managed to sort this.
Apparently the .dts files for the mpc8313erdb are in dts-v0 format. The vrsion of the DTC (Device Tree Compiler) I have installed does not support this format any longer.
To fix it I downloaded the source and built it, which includes a utility called convert-dtsv0
>git clone http://git.jdl.com/software/dtc.git
>cd dtc
>make
This should build the convert-dtsv0 utiltity
Copy it to your /usr/local/bin directory (or wherever you think is suitable in your PATH)
>cd /ltib-mpc8313erdb-20081222/config/platform/mpc8313erdb/dts/
(or wherever you have the BSP installed)
>convert-dtsv0 mpc8313erdb.dts
>convert-dtsv0 mpc8313erdb-revc-tsec1-marvell.dts
>convert-dtsv0 mpc8313erdb-usb-internal-client.dts
This will produce three files of the same names, but with the extension .dtsv1
You will need to delete or rename the original files to something else (I renamed them with an extra .orig extension), then rename the .dtsv1 files to .dts
The build should now work. (hopefully)