tests: drivers: spi: spi_loopback: update spi_loopback test

add nucleo_wba55cg board for spi_loopback driver test.

Signed-off-by: Fabrice DJIATSA <fabrice.djiatsa-ext@st.com>

Author: djiatsaf-st

tests/drivers/spi/spi_loopback/boards/nucleo_wba55cg.overlay

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&rcc {
+	apb2-prescaler = <2>;
+};
+
+&spi1 {
+	dmas = <&gpdma1 0 7 STM32_DMA_PERIPH_TX
+		&gpdma1 1 6 STM32_DMA_PERIPH_RX>;
+	dma-names = "tx", "rx";
+	slow@0 {
+		compatible = "test-spi-loopback-slow";
+		reg = <0>;
+		spi-max-frequency = <500000>;
+	};
+	fast@0 {
+		compatible = "test-spi-loopback-fast";
+		reg = <0>;
+		spi-max-frequency = <16000000>;
+	};
+};
+
+&gpdma1 {
+	status = "okay";
+};

tests/drivers/spi/spi_loopback/testcase.yaml

@@ -72,6 +72,7 @@ tests:
       - nucleo_f429zi
       - nucleo_f746zg
       - nucleo_f767zi
+      - nucleo_wba55cg
       - nucleo_wb55rg
       - nucleo_l152re
       - nucleo_wl55jc
@@ -134,6 +135,7 @@ tests:
       - nucleo_h745zi_q/stm32h745xx/m4
       - nucleo_h745zi_q/stm32h745xx/m7
       - nucleo_l152re
+      - nucleo_wba55cg
       - nucleo_wb55rg
       - nucleo_wl55jc
       - stm32f3_disco