[nrf fromtree] tests: drivers: spi: Add support for nRF54L09 PDK

Added support for nRF54L09 PDK in SPIM twister tests.

Signed-off-by: Michał Stasiak <[email protected]>
(cherry picked from commit ccd2fd6)

Author: mstasiaknordic

tests/drivers/spi/spi_loopback/boards/nrf54l09pdk_nrf54l09_cpuapp.overlay

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&pinctrl {
+	spi21_default: spi21_default {
+		group1 {
+			psels = <NRF_PSEL(SPIM_SCK, 1, 6)>,
+				<NRF_PSEL(SPIM_MISO, 1, 9)>,
+				<NRF_PSEL(SPIM_MOSI, 1, 8)>;
+		};
+	};
+
+	spi21_sleep: spi21_sleep {
+		group1 {
+			psels = <NRF_PSEL(SPIM_SCK, 1, 6)>,
+				<NRF_PSEL(SPIM_MISO, 1, 9)>,
+				<NRF_PSEL(SPIM_MOSI, 1, 8)>;
+			low-power-enable;
+		};
+	};
+};
+
+&spi21 {
+	status = "okay";
+	pinctrl-0 = <&spi21_default>;
+	pinctrl-1 = <&spi21_sleep>;
+	pinctrl-names = "default", "sleep";
+	overrun-character = <0x00>;
+	zephyr,pm-device-runtime-auto;
+	slow@0 {
+		compatible = "test-spi-loopback-slow";
+		reg = <0>;
+		spi-max-frequency = <DT_FREQ_M(2)>;
+	};
+	fast@0 {
+		compatible = "test-spi-loopback-fast";
+		reg = <0>;
+		spi-max-frequency = <DT_FREQ_M(4)>;
+	};
+};
+
+&gpio1 {
+	status = "okay";
+};