spi: lpspi: add dmas property

The LPSPI has dma capability, so add dma property.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220812073452.45763-1-peng.fan@oss.nxp.com


Signed-off-by: Mark Brown <broonie@kernel.org>