dt-bindings: dmaengine: xilinx_dma: Fix formatting and style

address and a memory-mapped destination address.

Required properties:

- compatible: Should be "xlnx,axi-vdma-1.00.a" or "xlnx,axi-dma-1.00.a" or

	      "xlnx,axi-cdma-1.00.a""

- compatible: Should be one of-

		"xlnx,axi-vdma-1.00.a"

		"xlnx,axi-dma-1.00.a"

		"xlnx,axi-cdma-1.00.a"

- #dma-cells: Should be <1>, see "dmas" property below

- reg: Should contain VDMA registers location and length.

- xlnx,addrwidth: Should be the vdma addressing size in bits(ex: 32 bits).

			   "m_axis_mm2s_aclk", "s_axis_s2mm_aclk"

	For CDMA:

	Required elements: "s_axi_lite_aclk", "m_axi_aclk"

	FOR AXIDMA:

	For AXIDMA:

	Required elements: "s_axi_lite_aclk"

	Optional elements: "m_axi_mm2s_aclk", "m_axi_s2mm_aclk",

			   "m_axi_sg_aclk"