riscv: dts: sophgo: fix DMA data-width configuration for CV18xx

The "snps,data-width" property[1] defines the AXI data width of the DMA
controller as:

    width = 8 × (2^n) bits

(0 = 8 bits, 1 = 16 bits, 2 = 32 bits, ..., 6 = 512 bits)
where "n" is the value of "snps,data-width".

For the CV18xx DMA controller, the correct AXI data width is 32 bits,
corresponding to "snps,data-width = 2".

Test results on Milkv Duo S can be found here [2].

Link: https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/dma/snps%2Cdw-axi-dmac.yaml#L74 [1]
Link: https://gist.github.com/Sutter099/4fa99bb2d89e5af975983124704b3861 [2]

Fixes: 514951a ("riscv: dts: sophgo: cv18xx: add DMA controller")
Co-developed-by: Yu Yuan <[email protected]>
Signed-off-by: Yu Yuan <[email protected]>
Signed-off-by: Ze Huang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Inochi Amaoto <[email protected]>
Signed-off-by: Chen Wang <[email protected]>
Signed-off-by: Chen Wang <[email protected]>

Author: Sutter099

arch/riscv/boot/dts/sophgo/cv18xx.dtsi

@@ -341,7 +341,7 @@
 					   1024 1024 1024 1024>;
 			snps,priority = <0 1 2 3 4 5 6 7>;
 			snps,dma-masters = <2>;
-			snps,data-width = <4>;
+			snps,data-width = <2>;
 			status = "disabled";
 		};