ASoC: spacemit: advertise only DMA-backed DAI streams

ASoC: spacemit: advertise only DMA-backed DAI streams

The static DAI template initializes both playback and capture stream
capabilities before dma-names is examined. As a result,
snd_soc_dai_stream_valid() considers both directions valid even when the
device only provides a single DMA channel.

Move the playback and capture capability initialization into
spacemit_i2s_init_dai(), where it is performed only for the stream
directions backed by a corresponding DMA channel. This preserves the
existing capabilities for devices with both "tx" and "rx" DMA channels,
while preventing unsupported stream directions from being advertised.

Initialize rate_min and rate_max together with the other stream
capabilities to preserve the existing rate constraints.

Fixes: fce217449075 ("ASoC: spacemit: add i2s support for K1 SoC")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
Link: https://patch.msgid.link/20260805064348.44283-1-phucduc.bui@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>