tests: drivers: uart: uart_async_api: Add the missing overlay file

Add the overlay file to enable the DMA driver to fix the
compilation error

Signed-off-by: Sreeram Tatapudi <[email protected]>

Author: sreeramIfx

tests/drivers/uart/uart_async_api/boards/cy8cproto_063_ble.overlay

@@ -0,0 +1,11 @@
+&dma0 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	compatible = "infineon,cat1-dma";
+	status = "okay";
+};
+
+dut: &scb5 {
+	dmas = <&dma0 22>, <&dma0 23>;
+	dma-names = "tx", "rx";
+};