topology: add support to parse private data for pcm

We have private data section in struct snd_soc_tplg_pcm, but alsatplg
doesn't support handling it yet, here add handling in tplg_parse_pcm()
to enable it.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/topology/pcm.c

@@ -732,6 +732,14 @@ int tplg_parse_pcm(snd_tplg_t *tplg,
 				return err;
 			continue;
 		}
+
+		/* private data */
+		if (strcmp(id, "data") == 0) {
+			err = tplg_parse_data_refs(n, elem);
+			if (err < 0)
+				return err;
+			continue;
+		}
 	}
 
 	return 0;