Add DMA mode support for the Spreadtrum SPI controller, and we will enable
SPI interrupt to help to complete the SPI transfer work in DMA mode.
Signed-off-by: Lanqing Liu <lanqing.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>