ARM: dts: at91: Fix matrix compatible

The matrix node was defined before the documentation for the bus
matrix configuration was submitted. Patch the device tree to match
the DT doc.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

arch/arm/boot/dts/at91sam9261.dtsi

@@ -263,7 +263,7 @@ ramc: ramc@ffffea00 {
 			};
 
 			matrix: matrix@ffffee00 {
-				compatible = "atmel,at91sam9260-bus-matrix", "syscon";
+				compatible = "atmel,at91sam9261-matrix", "syscon";
 				reg = <0xffffee00 0x200>;
 			};