ARM: dts: arria5: add board compatible for SoCFPGA DK

The Altera SoCFPGA Arria V SoC Development Kit is a board with Arria 5,
so it needs its own compatible.
Signed-off-by: NKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: NDinh Nguyen <dinguyen@kernel.org>

arch/arm/boot/dts/socfpga_arria5_socdk.dts

@@ -7,7 +7,7 @@
 
 / {
 	model = "Altera SOCFPGA Arria V SoC Development Kit";
-	compatible = "altr,socfpga-arria5", "altr,socfpga";
+	compatible = "altr,socfpga-arria5-socdk", "altr,socfpga-arria5", "altr,socfpga";
 
 	chosen {
 		bootargs = "earlyprintk";