arm64: zynqmp: Wire spi-flash compatible string with flashes

Enable reading tx and rx buswidth from DT via spi-uclass.
To get these from uclass spi-flash compatible string has to be added
to flash node.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/dts/zynqmp-zcu111-revA.dts b/arch/arm/dts/zynqmp-zcu111-revA.dts
index 6c1a0f7..346e631 100644
--- a/arch/arm/dts/zynqmp-zcu111-revA.dts
+++ b/arch/arm/dts/zynqmp-zcu111-revA.dts
@@ -449,7 +449,7 @@
 	status = "okay";
 	is-dual = <1>;
 	flash@0 {
-		compatible = "m25p80"; /* 32MB */
+		compatible = "m25p80", "spi-flash"; /* 32MB */
 		#address-cells = <1>;
 		#size-cells = <1>;
 		reg = <0x0>;