topology1: pipe-volume-capture.m4: Set minimum number of channels to 2

Currently, the minimum number of channels for the capture PCM
is set to the same value as the maximum number. This restricts
the number of channels supported by the PCM to the maximum number.
This is wrong if we want to allow arecord to work with multiple channel
values. As such, follow the example of "pipe-volume-playback.m4" and
introduce a new macro: LOCAL_CHANNELS_MIN. This will be set to
"CHANNELS_MIN" if said macro is defined, otherwise it will be set to
2.

Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>

tools/topology/topology1/sof/pipe-volume-capture.m4

@@ -72,10 +72,13 @@ P_GRAPH(pipe-volume-capture, PIPELINE_ID,
 indir(`define', concat(`PIPELINE_SINK_', PIPELINE_ID), N_BUFFER(1))
 indir(`define', concat(`PIPELINE_PCM_', PIPELINE_ID), Passthrough Capture PCM_ID)
 
+ifdef(`CHANNELS_MIN', `define(`LOCAL_CHANNELS_MIN', `CHANNELS_MIN')',
+`define(`LOCAL_CHANNELS_MIN', `2')')
+
 #
 # PCM Configuration
 #
 
 PCM_CAPABILITIES(Passthrough Capture PCM_ID, CAPABILITY_FORMAT_NAME(PIPELINE_FORMAT),
-	PCM_MIN_RATE, PCM_MAX_RATE, PIPELINE_CHANNELS, PIPELINE_CHANNELS,
+	PCM_MIN_RATE, PCM_MAX_RATE, LOCAL_CHANNELS_MIN, PIPELINE_CHANNELS,
 	2, 16, 192, 16384, 65536, 65536)