Your patch actually addresses an issue which I have seen with RTL_SPI_SFCSR_CS.
Since you seem to have boards with these Realtek SoCs: could you
please clean up your patch and upstream it (splitting into smaller
patches if/where needed)? That would be a win-win: upstream gains
improved SPI support and I won't be confused the next time I look at
the spi-realtek-rtl driver.