ARM: dts: stm32f429: Add QSPI clock

This patch adds the QSPI clock for stm32f469 discovery board.
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32f469-disco.dts

@@ -70,6 +70,10 @@ soc {
 	};
 };
 
+&rcc {
+	compatible = "st,stm32f469-rcc", "st,stm32f42xx-rcc", "st,stm32-rcc";
+};
+
 &clk_hse {
 	clock-frequency = <8000000>;
 };