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_xm011_defconfig b/configs/zynq_zc770_xm011_defconfig
index c15877d..70a76e6 100644
--- a/configs/zynq_zc770_xm011_defconfig
+++ b/configs/zynq_zc770_xm011_defconfig
@@ -6,7 +6,7 @@
 CONFIG_DEBUG_UART_CLOCK=50000000
 CONFIG_IDENT_STRING=" Xilinx Zynq ZC770 XM011"
 CONFIG_SPL_STACK_R_ADDR=0x200000
-# CONFIG_SPL_FAT_SUPPORT is not set
+# CONFIG_SPL_FS_FAT is not set
 CONFIG_DEBUG_UART=y
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT=y