Kconfig: Migrate FS_FAT / FAT_WRITE

Now that these symbols are in Kconfig, migrate all users.  Use imply on
a number of platforms that default to having this enabled.  As part of
this we must migrate some straglers for CMD_FAT and DOS_PARTITION.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/socfpga_arria10_socdk.h b/include/configs/socfpga_arria10_socdk.h
index 7ea780b..3b59b6a 100644
--- a/include/configs/socfpga_arria10_socdk.h
+++ b/include/configs/socfpga_arria10_socdk.h
@@ -8,8 +8,7 @@
 #define __CONFIG_SOCFGPA_ARRIA10_H__
 
 #include <asm/arch/base_addr_a10.h>
-/* U-Boot Commands */
-#define CONFIG_FAT_WRITE
+
 #define CONFIG_HW_WATCHDOG
 
 /* Booting Linux */