hal: fix debug logs compilation error

Fix compilation error after enabling debug logs

CRs-Fixed: 2416551
Change-Id: Ida84a1bf852ead2bb2ee7ad822427b15ebbbe59f
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index a86e752..9205086 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -8173,6 +8173,7 @@
             if (retval >= 0) {
                 *pparams = pcm_params_get(card_id, device_id, flags_dir);
 #if LOG_NDEBUG == 0
+                char info[512]; /* for possible debug info */
                 if (*pparams) {
                     ALOGV("%s: (%s) card %d  device %d", __func__,
                             dir ? "input" : "output", card_id, device_id);