[5.4/5.10/5.15/6.1/6.6] spi-mxs: Fix chipselect glitch

[Stefan Wahren <wahrenst@xxxxxxx>]

Dear stable team,

I noticed that ceeeb99cd821 ("dmaengine: mxs: rename custom flag") got backported, but the additional fix 269e31aecdd0 ("spi-mxs: Fix chipselect glitch") hasn't.
I think was caused by the lack of Cc to stable. Without the latter patch the SPI is causing glitches on MXS platform.

Please backport it from 5.4 to 6.6.

Thanks
Stefan