arm: Disable SPL_FS_FAT when it isn't used

arm: Disable SPL_FS_FAT when it isn't used

Several boards enable SPL_FS_FAT and SPL_LIBDISK_SUPPORT when they can't be
used (as there is no block device support enabled). Disable these configs.
The list of boards was generated with the following command:

    $ tools/qconfig.py -f SPL SPL_FS_FAT ~SPL_MMC ~SPL_BLK_FS ~SPL_SATA \
                          ~SPL_USB_STORAGE ~ENV_IS_IN_FAT ~EFI

LIBDISK was left enabled for the am* boards, since it seems to result in
actual size reduction, indicating that partitions are being used for
something.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Michal Simek <michal.simek@amd.com>