ARM: zynq: Use recommended dma-controller name instead of dmac

Use standard name for dma controller. Issue is reported by dtbs_check as
dmac@f8003000: $nodename:0: 'dmac@f8003000' does not match
'^dma-controller(@.*)?$'

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/5637d7e3464fbc1b2b269a7df35e24edc2c8d4ac.1672908080.git.michal.simek@amd.com