Rename some defines containing FAT in their name to be filesystem generic

Rename some defines containing FAT in their name to be filesystem generic:
MMCSD_MODE_FAT => MMCSD_MODE_FS
CONFIG_SPL_FAT_LOAD_ARGS_NAME => CONFIG_SPL_FS_LOAD_ARGS_NAME
CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME => CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION => CONFIG_SYS_MMC_SD_FS_BOOT_PARTITION

Signed-off-by: Guillaume GARDET <guillaume.gardet@free.fr>
Cc: Tom Rini <trini@ti.com>
diff --git a/include/configs/mcx.h b/include/configs/mcx.h
index cd85a6c..adaf44f 100644
--- a/include/configs/mcx.h
+++ b/include/configs/mcx.h
@@ -372,8 +372,8 @@
 #define CONFIG_SPL_BSS_MAX_SIZE		0x80000
 
 #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR	0x300 /* address 0x60000 */
-#define CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION	1
-#define CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME	"u-boot.img"
+#define CONFIG_SYS_MMC_SD_FS_BOOT_PARTITION	1
+#define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME	"u-boot.img"
 
 /* NAND boot config */
 #define CONFIG_SYS_NAND_PAGE_COUNT	64