post_proc: fix mul-overflow

Fix mul-overflow due to uninitialized value being used.

Change-Id: I97d1f63534aa6f5ac28357bf489796607747b162
diff --git a/post_proc/equalizer.c b/post_proc/equalizer.c
index ed16f12..a2e69b0 100644
--- a/post_proc/equalizer.c
+++ b/post_proc/equalizer.c
@@ -517,6 +517,8 @@
     set_config(context, &context->config);
 
     eq_ctxt->hw_acc_fd = -1;
+    for (int i = 0; i < NUM_EQ_BANDS; i++)
+        eq_ctxt->band_levels[i] = 0;
     memset(&(eq_ctxt->offload_eq), 0, sizeof(struct eq_params));
     offload_eq_set_preset(&(eq_ctxt->offload_eq), INVALID_PRESET);
     enable_gcov();