ASoC: wcd9310: Add check to prevent the wrap around of channel active value

If the value of channel active variable is zero, don't decrease it.

Change-Id: Ic9cf9faacc10c37b30f2e3d91700015669061c24
Signed-off-by: Helen Zeng <xiaoyunz@codeaurora.org>
diff --git a/sound/soc/codecs/wcd9310.c b/sound/soc/codecs/wcd9310.c
index 7eefe97..e85e9f5 100644
--- a/sound/soc/codecs/wcd9310.c
+++ b/sound/soc/codecs/wcd9310.c
@@ -4256,7 +4256,8 @@
 				continue;
 			if (!strncmp(w->sname,
 				tabla_dai[j].playback.stream_name, 13)) {
-				--tabla_p->dai[j].ch_act;
+				if (tabla_p->dai[j].ch_act)
+					--tabla_p->dai[j].ch_act;
 				break;
 			}
 		}