cras_stream_apm: Allow all channels

We don't want to use FC to pass the 3rd channel for beamforming
because when a client requests mono and beamforming is not enabled,
CRAS might picked up FC as mono, while it's preferred to mix FL+FR
in that case.

BUG=b:261951580
TEST=bazel test //...
TEST=tast run dut12 audio.CrasMultiChannelCapture.\* audio.CrasAEC.\*

Change-Id: I13e7744016034e3bce5e178d4401e867a9d49580
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/5534462
Commit-Queue: Li-Yu Yu <[email protected]>
Tested-by: [email protected] <[email protected]>
Reviewed-by: Pattara Teerapong <[email protected]>

Author: afq984

cras/src/server/cras_stream_apm.c

@@ -592,9 +592,7 @@ static struct cras_audio_format get_best_channels(
     apm_fmt.channel_layout[ch] = -1;
   }
 
-  int apm_valid_channels[] = {CRAS_CH_FL, CRAS_CH_FR, CRAS_CH_FC};
-  for (int i = 0; i < ARRAY_SIZE(apm_valid_channels); i++) {
-    int ch = apm_valid_channels[i];
+  for (int ch = CRAS_CH_FL; ch < CRAS_CH_MAX; ch++) {
     if (dev_fmt->channel_layout[ch] != -1) {
       apm_fmt.channel_layout[ch] = apm_fmt.num_channels++;
     }