ASoC: dpcm: Properly initialise hw->rate_max

If the CPU DAI does not initialise rate_max, say if using
using KNOT or CONTINUOUS, then the rate_max field will be
initialised to 0. A value of zero in the rate_max field of
the hardware runtime will cause the sound card to support no
sample rates at all. Obviously this is not desired, just a
different mechanism is being used to apply the constraints. As
such update the setting of rate_max in dpcm_init_runtime_hw
to be consistent with the non-DPCM cases and set rate_max to
UINT_MAX if nothing is defined on the CPU DAI.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-pcm.c

@@ -1680,7 +1680,7 @@ static void dpcm_init_runtime_hw(struct snd_pcm_runtime *runtime,
 				 struct snd_soc_pcm_stream *stream)
 {
 	runtime->hw.rate_min = stream->rate_min;
-	runtime->hw.rate_max = stream->rate_max;
+	runtime->hw.rate_max = min_not_zero(stream->rate_max, UINT_MAX);
 	runtime->hw.channels_min = stream->channels_min;
 	runtime->hw.channels_max = stream->channels_max;
 	if (runtime->hw.formats)