ARM: dts: stm32: Use kernel qspi compatible string for stm32f469-disco-uboot.dtsi

For STM32 QSPI driver, "st,stm32-qspi" compatible string was first
introduced in U-boot. But later in kernel side, "st,stm32f469-qspi"
was used.
To simplify, align U-boot QSPI compatible string with kernel one.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/dts/stm32f469-disco-u-boot.dtsi b/arch/arm/dts/stm32f469-disco-u-boot.dtsi
index 2409cf7..5a89f13 100644
--- a/arch/arm/dts/stm32f469-disco-u-boot.dtsi
+++ b/arch/arm/dts/stm32f469-disco-u-boot.dtsi
@@ -67,7 +67,7 @@
 		};
 
 		qspi: quadspi@A0001000 {
-			compatible = "st,stm32-qspi";
+			compatible = "st,stm32f469-qspi";
 			#address-cells = <1>;
 			#size-cells = <0>;
 			reg = <0xA0001000 0x1000>, <0x90000000 0x10000000>;