ARM: dts: stm32: keep uart nodes behavior on stm32mp15xx-dhcom-picoitx

DMA configuration is added to uart nodes in stm32mp15x device tree.
Delete usart3 and uart8 nodes DMA property in stm32mp15xx-dhcom-picoitx
board device tree to keep current behavior.

Signed-off-by: Erwan Le Ray <[e-mail]>
Signed-off-by: Alexandre Torgue <[e-mail]>

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

···
 &usart3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&usart3_pins_a>;
+	/delete-property/dmas;
+	/delete-property/dma-names;
 	status = "okay";
 };
 
 &uart8 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&uart8_pins_a &uart8_rtscts_pins_a>;
+	/delete-property/dmas;
+	/delete-property/dma-names;
 	status = "okay";
 };