armv8: fsl-layerscape: spl: fix the macro name of MMC mode

MMCSD_MODE_FAT has be renmaed to MMCSD_MODE_FS by commit 205b4f33.

Signed-off-by: Gong Qianyu <Qianyu.Gong@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/arm/cpu/armv8/fsl-layerscape/spl.c b/arch/arm/cpu/armv8/fsl-layerscape/spl.c
index 4c8a9a0..5883c00 100644
--- a/arch/arm/cpu/armv8/fsl-layerscape/spl.c
+++ b/arch/arm/cpu/armv8/fsl-layerscape/spl.c
@@ -29,7 +29,7 @@
 	switch (spl_boot_device()) {
 	case BOOT_DEVICE_MMC1:
 #ifdef CONFIG_SPL_FAT_SUPPORT
-		return MMCSD_MODE_FAT;
+		return MMCSD_MODE_FS;
 #else
 		return MMCSD_MODE_RAW;
 #endif