dt-bindings: dma: fsl-edma: fix dma-channels constraints

dt-bindings: dma: fsl-edma: fix dma-channels constraints

dma-channels is a number, not a list.  Apply proper constraints on the
actual number.

Fixes: 6eb439dff645 ("dt-bindings: fsl-dma: fsl-edma: add edma3 compatible string")
Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240521083002.23262-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>