arm64: dts: ls1043a: make dma-coherent global to the SoC

ls1043a is really completely dma coherent in their entirety so add the
dma-coherent property at the soc level in the device tree and drop the
instances where it's specifically added to a few select devices.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>