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/include/part.h b/include/part.h
index 388e130..ebca546 100644
--- a/include/part.h
+++ b/include/part.h
@@ -246,7 +246,7 @@
  */
 #ifdef CONFIG_SPL_BUILD
 # define part_print_ptr(x)	NULL
-# if defined(CONFIG_SPL_EXT_SUPPORT) || defined(CONFIG_SPL_FS_FAT) || \
+# if defined(CONFIG_SPL_FS_EXT4) || defined(CONFIG_SPL_FS_FAT) || \
 	defined(CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION)
 #  define part_get_info_ptr(x)	x
 # else