uboot-phytec

MX28: SPI: Supercharge the SPI driver

This change implements DMA chaining into SPI driver. This allows
the transfers to go much faster, while also fixing SF issues.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>