ASoC: rsnd: fixup rsnd_dma_of_path method for mod base common method

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

Current rsnd_dma_of_path is assuming that all mods are related to DMA.
But it will be wrong. This patch tidyup this wrong assumption

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>