Hello,
even though the subject sounds harmless it fixes a real bug.
(Yes, I'm aware that commit isn't in Linus' tree yet, but I assume your tracking of patches targetting stable is better than mine, so I didn't wait :-)
For backporting you also need its parent commit (i.e. e697271c4e29 ("spi: imx: add a device specific prepare_message callback")). I have a local backport to v4.14 here which isn't entirely trivial. So just tell me if you need help.
Best regards Uwe