Tegra20/Tegra30 supports the spi interface through its SLINK
controller. Add spi driver for SLINK controller.
Signed-off-by: NLaxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>