spi: atmel: Drop slave_config argument in atmel_spi_dma_slave_config()

The callers passed a pointer to slave_config as an argument of
atmel_spi_dma_slave_config(), but they did not use it afterwards.
Use instead a local variable in atmel_spi_dma_slave_config(), and
stop passing arguments that are not needed in the callers.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211125124110.838037-2-tudor.ambarus@microchip.com


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