[POWERPC] Fix mpc7448hpc2 tsi108 device_type bug

Fix mpc7448hpc2 tsi108 device_type bug.
Wrong device type will break the board startup.
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/boot/dts/mpc7448hpc2.dts

@@ -45,7 +45,7 @@
 		#address-cells = <1>;
 		#size-cells = <1>;
 		#interrupt-cells = <2>;
-		device_type = "tsi108-bridge";
+		device_type = "tsi-bridge";
 		ranges = <00000000 c0000000 00010000>;
 		reg = <c0000000 00010000>;
 		bus-frequency = <0>;