ARM: dts: stm32: Rename spi-flash/mx66l51235l@N to flash@N on DHCOM SoM

Fix the following dtbs_check warning:
spi-flash@0: $nodename:0: 'spi-flash@0' does not match '^flash(@.*)?$'
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: kernel@dh-electronics.com
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi

@@ -437,7 +437,7 @@ &qspi {
 	#size-cells = <0>;
 	status = "okay";
 
-	flash0: mx66l51235l@0 {
+	flash0: flash@0 {
 		compatible = "jedec,spi-nor";
 		reg = <0>;
 		spi-rx-bus-width = <4>;

arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi

@@ -198,7 +198,7 @@ &qspi {
 	#size-cells = <0>;
 	status = "okay";
 
-	flash0: spi-flash@0 {
+	flash0: flash@0 {
 		compatible = "jedec,spi-nor";
 		reg = <0>;
 		spi-rx-bus-width = <4>;