ARM: dts: imx23/28: Fix the DMA controller node name

[ Upstream commit 858d83ca4b50bbc8693d95cc94310e6d791fb2e6 ]

Per fsl,mxs-dma.yaml, the node name should be 'dma-controller'.

Change it to fix the following dt-schema warning.

imx28-apf28.dtb: dma-apbx@80024000: $nodename:0: 'dma-apbx@80024000' does not match '^dma-controller(@.*)?$'
	from schema $id: http://devicetree.org/schemas/dma/fsl,mxs-dma.yaml#



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