ARM: dts: stm32: keep uart4 behavior on stm32mp157a-iot-box

DMA configuration is added to uart nodes in stm32mp15x device tree.
Delete uart4 DMA property in stm32mp157a-iot-box board device tree to
keep console in irq mode, as DMA support for console has been removed
from the driver by commit e359b4411c28 ("serial: stm32: fix threaded
interrupt handling").

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

arch/arm/boot/dts/stm32mp157a-iot-box.dts

···
 	/delete-property/st,hw-flow-ctrl;
 	cts-gpios = <&gpioa 15 GPIO_ACTIVE_LOW>;
 	rts-gpios = <&gpiob 0 GPIO_ACTIVE_LOW>;
+	/delete-property/dmas;
+	/delete-property/dma-names;
 	status = "okay";
 
 	bluetooth {