spi: Updates for v3.15 A busy release for both cleanups and new drivers this time along with further factoring out of replicated code into the core: - Provide support in the core for DMA mapping transfers - essentially all drivers weren't implementing this properly, now there's no excuse. - Dual and quad mode support for spidev. - Fix handling of cs_change in the generic implementation. - Remove the S3C_DMA code from the s3c64xx driver now that all the platforms using it have been converted to dmaengine. - Lots of improvements to the Renesas SPI controllers. - Drivers for Allwinner A10 and A31, Qualcomm QUP and Xylinx xtfpga. - Removal of the bitrotted ti-ssp driver.