The CMD_CONFIG register memory interface type field is not set configured
for Dual and Quad modes, so set appropriately.

This was not detected previously as we only ever operated in standard SPI
mode.
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1582903131-160033-3-git-send-email-john.garry@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>