ARM: dts: ls1021a-qds: change fpga to simple-mfd device

The FPGA is not really a bus but more like an MFD device. Change the
compatible string from "simple-bus" to "simple-mfd". This also fix a
node name issue with simple-bus schema.

Signed-off-by: Li Yang <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/ls1021a-qds.dts

···
 	fpga: board-control@3,0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
-		compatible = "simple-bus";
+		compatible = "simple-mfd";
 		reg = <0x3 0x0 0x0000100>;
 		bank-width = <1>;
 		device-width = <1>;