ARM: dts: s5pv210: Adjust DMA node names to match spec

DMA node names should be dma-controller according to the DT spec,
so rename them from pdma/mdma.  Prevents warnings when running
make dtbs_check

Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
Link: https://lore.kernel.org/r/CY4PR04MB0567F52ABAE0A3CCD3C7CE59CB1C9@CY4PR04MB0567.namprd04.prod.outlook.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>