USB-Audio: Steinberg UR22C - fix capture channels for older firmware

It seems that firmware version 3.20 added 4 capture channels while
previous firmware has only 2 capture channels.

Fixes: alsa-project#547
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

Author: perexg

ucm2/USB-Audio/Steinberg/UR22C-HiFi.conf

@@ -6,7 +6,7 @@ Macro [
 			Name "steinberg_ur22c_mono_in"
 			Direction Capture
 			Channels 1
-			HWChannels 4
+			HWChannels "${var:DirectCaptureChannels}"
 			HWChannelPos0 MONO
 			HWChannelPos1 MONO
 		}
@@ -31,7 +31,7 @@ SectionDevice."Line 2" {
 	Macro.pcm_split.SplitPCMDevice {
 		Name "steinberg_ur22c_mono_in"
 		Direction Capture
-		HWChannels 4
+		HWChannels "${var:DirectCaptureChannels}"
 		Channels 1
 		Channel0 0
 		ChannelPos0 MONO
@@ -47,7 +47,7 @@ SectionDevice."Line 3" {
 	Macro.pcm_split.SplitPCMDevice {
 		Name "steinberg_ur22c_mono_in"
 		Direction Capture
-		HWChannels 4
+		HWChannels "${var:DirectCaptureChannels}"
 		Channels 1
 		Channel0 1
 		ChannelPos0 MONO

ucm2/USB-Audio/Steinberg/UR22C.conf

@@ -1,11 +1,20 @@
 Comment "Steinberg UR22C USB-Audio"
 
+Define.DirectPlaybackChannels 2
+Define.DirectCaptureChannels 4
+
+If.fw {
+	Condition {
+		Type RegexMatch
+		String "${sys-card:device/../bcdDevice}"
+		Match "0[12]??"
+	}
+	True.Define.DirectCaptureChannels 2
+}
+
 SectionUseCase."HiFi" {
 	Comment "HiFi"
 	File "/USB-Audio/Steinberg/UR22C-HiFi.conf"
 }
 
-Define.DirectPlaybackChannels 2
-Define.DirectCaptureChannels 2
-
 Include.dhw.File "/common/direct.conf"