dt-bindings: dma: snps,dw-axi-dmac: Allow devices to be marked as noncoherent

dt-bindings: dma: snps,dw-axi-dmac: Allow devices to be marked as noncoherent

A RISC-V platform can have both DMA coherent/noncoherent devices.
Since the RISC-V architecture is marked coherent, devices should
be marked as noncoherent when coherent devices exist.

Add dma-noncoherent property for snps,dw-axi-dmac device. It will
be used on SG2044, and it has other coherent devices.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250303065649.937233-1-inochiama@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>