tests: drivers: adc: adc_api: add stm32wba65i_dk1/ns board

Support the ns variant of stl32wba65i_dk1 board in ADC API tests.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>

Author: etienne-lms

tests/drivers/adc/adc_api/boards/stm32wba65i_dk1_stm32wba65xx_ns.overlay

@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2025 STMicroelectronics
+ */
+
+/ {
+	zephyr,user {
+		/* adjust channel number according to pinmux in board.dts */
+		io-channels = <&adc4 7>, <&adc4 8>;
+	};
+};
+
+&adc4 {
+	pinctrl-0 = <&adc4_in6_pa3 &adc4_in7_pa2 &adc4_in8_pa1>;
+
+	channel@7 {
+		reg = <7>;
+		zephyr,gain = "ADC_GAIN_1";
+		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,acquisition-time = <ADC_ACQ_TIME_MAX>;
+		zephyr,resolution = <12>;
+	};
+
+	channel@8 {
+		reg = <8>;
+		zephyr,gain = "ADC_GAIN_1";
+		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,acquisition-time = <ADC_ACQ_TIME_MAX>;
+		zephyr,resolution = <12>;
+	};
+};