ARM: at91: sama5d3: add usart dma configurations

Add the DMA configuration for USARTs mainly because it is not obvious to
add the FIFO flag which is needed for rx.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
1 file changed