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

We don't want to encourage the bogus device_type usage.

The device type isn't used in the code, so we can simply remove it from
the documentation and dts files.

Boards should specify proper compatible entries instead.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

Documentation/powerpc/dts-bindings/fsl/board.txt

@@ -2,13 +2,13 @@
 
 Required properties:
 
- - device_type : Should be "board-control"
+ - compatible : Should be "fsl,<board>-bcsr"
  - reg : Offset and length of the register set for the device
 
 Example:
 
 	bcsr@f8000000 {
-		device_type = "board-control";
+		compatible = "fsl,mpc8360mds-bcsr";
 		reg = <f8000000 8000>;
 	};