sunxi_nand_spl: Do not bother writing the spare-area reg in syndrome mode

sunxi_nand_spl: Do not bother writing the spare-area reg in syndrome mode

In syndrome mode we set the NFC_SEQ bit in the command register, so the
spare-area register is not used. Also the value currently being written is
actual wrong, the ecc sits at "column + CONFIG_NAND_SUNXI_SPL_ECC_PAGE_SIZE"
not just CONFIG_NAND_SUNXI_SPL_ECC_PAGE_SIZE.

So the current code only serves to confuse the user -> remove it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>