spi: spi-s3s64xx: Add S3C64XX_SPI_QUIRK_CS_AUTO for Exynos3250

Fix issues with DMA transfers bigger than 512 bytes on Exynos3250. Without
the patches such transfers fail.

The vendor kernel for ARTIK5 handles CS in a simmilar way.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201002122243.26849-3-l.stelmach@samsung.com


Signed-off-by: Mark Brown <broonie@kernel.org>