topology2: Add pcm capabilities class

Add pcm capabilities class definition, pcm
capabilities object can be instantiated as:

    Object.PCM.pcm_caps."DIRECTION" {
	name	    "Headset"
	direction   "playback"
	formats	    "S32_LE,S24_LE,S16_LE"
	rate_min	48000
	rate_max	48000
	channels_min	2
	channels_max	2
	periods_min	2
    }

Signed-off-by: Ranjani Sridharan <ranjani.sidharan@linux.intel.com>
Signed-off-by: Chao Song <chao.song@linux.intel.com>

tools/topology/topology2/include/common/pcm_caps.conf

@@ -0,0 +1,92 @@
+#
+# PCM Capabilities Class definition. All attributes defined herein are
+# namespaced by alsatplg to "Object.PCM.pcm_caps.DIRECTION.attribute_name".
+#
+# Usage: PCM object can be instantiated as:
+#
+#	Object.PCM.pcm_caps."DIRECTION" {
+#		name			"Headset"
+#		direction		"playback"
+#		formats			"S32_LE,S24_LE,S16_LE"
+#		rate_min		48000
+#		rate_max		48000
+#		channels_min		2
+#		channels_max		2
+#		periods_min		2
+#	}
+#
+# where DIRECTION is the unique stream direction for the pcm_caps object within
+# the same alsaconf node (normally, pcm object).
+
+Class.PCM."pcm_caps" {
+	#
+	# Argument used to construct PCM Capabilities
+	#
+	DefineAttribute."name" {
+		type	"string"
+	}
+
+	DefineAttribute."direction" {
+		type	"string"
+		!valid_values [
+			playback
+			capture
+		]
+	}
+
+	DefineAttribute."formats" {
+		type	"string"
+	}
+
+	DefineAttribute."rates" {
+		type	"string"
+	}
+
+	DefineAttribute."sigbits" {}
+
+	DefineAttribute."rate_min" {}
+
+	DefineAttribute."rate_max" {}
+
+	DefineAttribute."channels_min" {}
+
+	DefineAttribute."channels_max" {}
+
+	DefineAttribute."periods_min" {}
+
+	DefineAttribute."periods_max" {}
+
+	DefineAttribute."period_size_min" {}
+
+	DefineAttribute."period_size_max" {}
+
+	DefineAttribute."buffer_size_min" {}
+
+	DefineAttribute."buffer_size_max" {}
+
+	attributes {
+		!constructor [
+			"name"
+			"direction"
+		]
+
+		#
+		# pcm_caps objects instantiated within the same alsaconf node must have unique
+		# direction attribute
+		#
+		unique	"direction"
+	}
+
+	# Default attribute values for PCM capabilities
+	formats		"S32_LE,S24_LE,S16_LE"
+	rate_min		48000
+	rate_max		48000
+	periods_min		2
+	periods_max		16
+	channels_min		2
+	channels_max		2
+	period_size_min		192
+	period_size_max		16384
+	buffer_size_min		65536
+	buffer_size_max		65536
+}