spi: s3c64xx: Use DMA mode from fifo size

[ Upstream commit a3d3eab6 ]

If the SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO size, it oerates in DMA mode.

If the SPI data size is equal to fifo, it operates in PIO mode and it is
separated to 2 transfers. To prevent it, it must operate in DMA mode
from the case where the data size and the fifo size are the same.

Fixes: 1ee80671 ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20240329085840.65856-1-jaewon02.kim@samsung.com


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