dt-bindings: dmaengine: zynqmp_dma: add xlnx,bus-width required property

xlnx,bus-width is a required property. In yaml conversion somehow
it got missed out. Bring it back and mention it in required list.
Also add Harini and myself to the maintainer list.

Fixes: 5a04982d

 ("dt-bindings: dmaengine: zynqmp_dma: convert to yaml")
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Reviewed-by: Peter Korsgaard <peter@korsgaard.com>
Link: https://lore.kernel.org/r/1695216326-3841352-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>