st-hal: Fix double free in merge sound models logic

This change removes a double free of the confidence levels
structure which was causing a failure with repeated
load/start/stop/start usecases for dual VA.

Change-Id: I275925b8dbbdb8f46ad33ed063e5dee611d8a722
diff --git a/st_session.c b/st_session.c
index 31f415b..7bf02d9 100644
--- a/st_session.c
+++ b/st_session.c
@@ -1217,8 +1217,7 @@
     int hb_sz = 0, pr_sz = 0;
     bool active = false, enable_lab = false;
 
-    if (!st_ses->vendor_uuid_info->merge_fs_soundmodels ||
-        !st_ses->sm_info.sm_merged) {
+    if (!st_ses->vendor_uuid_info->merge_fs_soundmodels) {
         if (sthw_cfg->conf_levels) {
             ALOGV("%s: free hw conf_levels", __func__);
             free(sthw_cfg->conf_levels);