Use DMA for USART0 (which is used as ttyS1) as we have enough channels and to
show how to specify DMA use with serial nodes.
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>