MIPS: JZ4780: DTS: Update DMA node to match driver changes

The driver now accepts two memory resources, the first one for the
channel-specific registers, the second one for the controller-specific
registers.

Note that older devicetrees, without this commit, will still work with
the jz4780-dma driver.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>