spi: s3c64xx: support interrupt based pio mode

Support interrupt based pio mode to optimize cpu usage.
When transmitting data size is larget than 32 bytes, operates with
interrupt based pio mode.

By using the FIFORDY INT, an interrupt can be triggered when
the desired size of data has been received. Using this, we can support
interrupt based pio mode.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Link: https://lore.kernel.org/r/20230502062813.112434-4-jaewon02.kim@samsung.com


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