Fix s25fl256s position in spi_flash_ids list

Spansion S25FS256S and S25FL256S flashes have equal JEDEC ID and ext ID.
As far as S25FL256S occures in spi_flash_ids before S25FS256S, U-Boot
incorrectly detects FS flash as FL. Thus its better to compare with
S25FS256S first.

Signed-off-by: Vsevolod Gribov <vgribov@larch-networks.com>
[Added S-o-b]
Signed-off-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>