uboot-imx

sunxi_nand_spl: Add proper cache flusing

We are using dma, so we should flush the cache before starting the dma,
and invalidate it once the dma is done.

Things are working without this by mostly luck, but lets not rely on that.

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