spl: Kconfig: Replace CONFIG_SPL_EXT_SUPPORT to CONFIG_SPL_FS_EXT4

Replace CONFIG_SPL_EXT_SUPPORT to CONFIG_SPLY_FS_EXT4 so both
obj-$(CONFIG_$(SPL_)FS_EXT4) and CONFIG_IS_ENABLED(FS_EXT4) can be
used to control the build in both SPL and U-Boot.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
index e526167..324d91c 100644
--- a/common/spl/spl_mmc.c
+++ b/common/spl/spl_mmc.c
@@ -253,7 +253,7 @@
 		return err;
 #endif
 #endif
-#ifdef CONFIG_SPL_EXT_SUPPORT
+#ifdef CONFIG_SPL_FS_EXT4
 	if (!spl_start_uboot()) {
 		err = spl_load_image_ext_os(spl_image, mmc_get_blk_desc(mmc),
 			CONFIG_SYS_MMCSD_FS_BOOT_PARTITION);
@@ -269,7 +269,7 @@
 #endif
 #endif
 
-#if defined(CONFIG_SPL_FS_FAT) || defined(CONFIG_SPL_EXT_SUPPORT)
+#if defined(CONFIG_SPL_FS_FAT) || defined(CONFIG_SPL_FS_EXT4)
 	err = -ENOENT;
 #endif
 
@@ -284,7 +284,7 @@
 
 u32 __weak spl_boot_mode(const u32 boot_device)
 {
-#if defined(CONFIG_SPL_FS_FAT) || defined(CONFIG_SPL_EXT_SUPPORT)
+#if defined(CONFIG_SPL_FS_FAT) || defined(CONFIG_SPL_FS_EXT4)
 	return MMCSD_MODE_FS;
 #elif defined(CONFIG_SUPPORT_EMMC_BOOT)
 	return MMCSD_MODE_EMMCBOOT;