ARM: SAMSUNG: Make dma request compatible to generic dma bindings.

This patch make the dma dev request operation compatible for both
DT and non-DT cases. It takes the all the arguments required for
dma_request_slave_channel and dma_request_channel. If the driver
is initiated via DT or non-DT the corresponding call will be made.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>