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/am335x_shc_ict_defconfig b/configs/am335x_shc_ict_defconfig
index 0dbab0b..fb4c319 100644
--- a/configs/am335x_shc_ict_defconfig
+++ b/configs/am335x_shc_ict_defconfig
@@ -8,7 +8,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL=y
-CONFIG_SPL_FAT_SUPPORT=y
+CONFIG_SPL_FS_FAT=y
 CONFIG_SPL_LIBDISK_SUPPORT=y
 CONFIG_SHC_ICT=y
 CONFIG_SERIES=y