tests: drivers: adc_api: Add support for the Raspberry Pi Pico 2

For these tests' needs, the RP2350 on the Pico 2 is compatible with the
RP2040 on the Pico 1. #include the latter's overlay in preference to
duplicating the content.

Signed-off-by: Andrew Featherstone <[email protected]>

Author: ajf58

tests/drivers/adc/adc_api/boards/rpi_pico2_rp2350a_m33.overlay

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2024 Andrew Featherstone <[email protected]>
+ */
+
+/* Pico 2 is compatible with the Pico 1, so reuse. */
+#include "rpi_pico.overlay"
+
+&adc {
+	status = "okay";
+};