platform: msm_shared: free smd channel if it is not NULL

smd channel should be freed only if it is not NULL.

Change-Id: I0cb417e0bec198303429bbbc55dbe17f6aa7b824
diff --git a/platform/msm_shared/smd.c b/platform/msm_shared/smd.c
index 6ead08e..7ebbcbd 100644
--- a/platform/msm_shared/smd.c
+++ b/platform/msm_shared/smd.c
@@ -433,7 +433,11 @@
 	if(ch->current_state == SMD_SS_CLOSED)
 	{
 		flush_smd_channel_entries();
-		free(smd_channel_alloc_entry);
+		if(smd_channel_alloc_entry)
+		{
+			free(smd_channel_alloc_entry);
+			smd_channel_alloc_entry = NULL;
+		}
 		event_signal(&smd_closed, false);
 		return INT_NO_RESCHEDULE;
 	}