spl: Kconfig: Replace CONFIG_SPL_FAT_SUPPORT with CONFIG_SPL_FS_FAT

Replace CONFIG_SPL_FAT_SUPPORT with CONFIG_SPL_FS_FAT so
obj-$(CONFIG_$(SPL_)FS_FAT) 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: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/zynq_zc770_xm013_defconfig b/configs/zynq_zc770_xm013_defconfig
index a08bd29..630e392 100644
--- a/configs/zynq_zc770_xm013_defconfig
+++ b/configs/zynq_zc770_xm013_defconfig
@@ -4,7 +4,7 @@
 CONFIG_SPL=y
 CONFIG_IDENT_STRING=" Xilinx Zynq ZC770 XM013"
 CONFIG_SPL_STACK_R_ADDR=0x200000
-# CONFIG_SPL_FAT_SUPPORT is not set
+# CONFIG_SPL_FS_FAT is not set
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y