tests: sdmmc: add STM32H747I Disco M7 test configuration

Add configuration and devicetree overlay files
to enable running SDMMC subsystem tests on the STM32H747I
Discovery M7 core.

Signed-off-by: Sara Touqan <zephyr@exalt.ps>
Signed-off-by: Sarah Younis <zephyr@exalt.ps>
Signed-off-by: Mohammad Odeh <zephyr@exalt.ps>

Author: ExaltZephyr

tests/subsys/sd/sdmmc/boards/stm32h747i_disco_stm32h747xx_m7.conf

@@ -0,0 +1,4 @@
+# Copyright (c) 2025 EXALT Technologies.
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_HEAP_MEM_POOL_SIZE=2048

tests/subsys/sd/sdmmc/boards/stm32h747i_disco_stm32h747xx_m7.overlay

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 EXALT Technologies.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		sdhc0 = &sdhc;
+	};
+};
+
+sdhc: &sdmmc1 {
+	compatible = "st,stm32-sdhc";
+	interrupts = <49 0>;
+	interrupt-names = "event";
+	hw-flow-control;
+	bus-width = <4>;
+	status = "okay";
+	min-bus-freq = <DT_FREQ_K(400)>;
+	max-bus-freq = <DT_FREQ_M(208)>;
+	/delete-property/ disk-name;
+};