arm64: zynqmp: Add spi-flash compatible string to flash node

spi-flash compatible string is needed for reading tx and rx bus
widths, hence add this compatible string to flash node.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/dts/zynqmp-mini-qspi.dts b/arch/arm/dts/zynqmp-mini-qspi.dts
index c235a5f..49e8a42 100644
--- a/arch/arm/dts/zynqmp-mini-qspi.dts
+++ b/arch/arm/dts/zynqmp-mini-qspi.dts
@@ -64,7 +64,7 @@
 &qspi {
 	status = "okay";
 	flash@0 {
-		compatible = "n25q512a11";
+		compatible = "n25q512a11", "spi-flash";
 		#address-cells = <1>;
 		#size-cells = <1>;
 		reg = <0x0>;