Quoting from mt8183 datasheet, the number of transfers to be
transferred in one transaction should be set to bigger than 1,
so we should forbid zero-length transfer and update functionality.
Reported-by: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Qii Wang <qii.wang@mediatek.com>
[wsa: shortened commit message a little]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>