arm64: dts: imx8dxl-evk: Use audio-graph-card2 for wm8960-2 and wm8960-3

arm64: dts: imx8dxl-evk: Use audio-graph-card2 for wm8960-2 and wm8960-3

The sound card wm8960-2 and wm8960-3 only support capture mode for the
reason of connection on the EVK board. But fsl-asoc-card don't support
capture_only setting, the sound card creation will fail.

fsl-sai 59060000.sai: Missing dma channel for stream: 0
fsl-sai 59060000.sai: ASoC error (-22): at snd_soc_pcm_component_new() on 59060000.sai
fsl-sai 59070000.sai: Missing dma channel for stream: 0
fsl-sai 59070000.sai: ASoC error (-22): at snd_soc_pcm_component_new() on 59070000.sai

so switch to use audio-graph-card2 which supports 'capture_only'
property for wm8960-2 and wm8960-3 cards.

Fixes: b41c45eb990a ("arm64: dts: imx8dxl-evk: add audio nodes")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>