tests: subsys: fs: Support tests/subsys/fs on MCK_RA8T2 board

Add overlay property node and configs to support on MCK_RA8T2
- tests/subsys/fs/ext2
- tests/fs/fat_fs_api

Signed-off-by: Khoa Tran <[email protected]>

Author: khoatranyj

tests/subsys/fs/ext2/boards/mck_ra8t2_r7ka8t2lfecac_cm85.overlay

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2024 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&sdhc0 {
+	sdmmc {
+		partition {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size_cells = <1>;
+			slot1_partition: partition@0 {
+				reg = <0x00000000 0x800000>;
+			};
+		};
+	};
+};

tests/subsys/fs/fat_fs_api/boards/mck_ra8t2_r7ka8t2lfecac_cm85.conf

@@ -0,0 +1,4 @@
+CONFIG_MAIN_STACK_SIZE=4096
+CONFIG_DISK_DRIVER_RAM=n
+CONFIG_DISK_DRIVER_FLASH=n
+CONFIG_FS_FATFS_HAS_RTC=n