riscv: Extend board compatible string with "qemu,mbv"

Extend compatible string to match the latest change in dt binding.

Fixes: 7576ab2facae ("riscv: Add support for AMD/Xilinx MicroBlaze V")
Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/arch/riscv/dts/xilinx-mbv32.dts b/arch/riscv/dts/xilinx-mbv32.dts
index 6a6b8b6..94e42c2 100644
--- a/arch/riscv/dts/xilinx-mbv32.dts
+++ b/arch/riscv/dts/xilinx-mbv32.dts
@@ -12,7 +12,7 @@
 	#address-cells = <1>;
 	#size-cells = <1>;
 	model = "AMD MicroBlaze V 32bit";
-	compatible = "amd,mbv";
+	compatible = "qemu,mbv", "amd,mbv";
 
 	cpus: cpus {
 		#address-cells = <1>;