ARM: dts: bcm2835: adjust DMA node names

After converting the bcm2835-dma DT binding to YAML, the DT schema
checks gave warnings like:

$nodename:0: 'dma@7e007000' does not match '^dma-controller(@.*)?$'

So fix them accordingly.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/20230617133620.53129-4-stefan.wahren@i2se.com


Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>