ARM: dts: imx1/imx27: Use dma-controller as node name

According to fsl,imx-dma.yaml, the node name must be dma-controller.

Change it accordingly to fix the following dt-schema warnings:

'dma@10001000' does not match '^dma-controller(@.*)?$'

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>