audio/mixeng: use g_new0() instead of audio_calloc()

Replace audio_calloc() with the equivalent g_new0().

With a n_structs argument of 1, g_new0() never returns NULL.
Also remove the unnecessary NULL checks.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230121094735.11644-5-vr_qemu@t-online.de>
diff --git a/audio/audio.c b/audio/audio.c
index 81f5c0b..012d109 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -509,11 +509,6 @@
         sw->ratio = ((int64_t) hw_cap->info.freq << 32) / sw->info.freq;
         sw->vol = nominal_volume;
         sw->rate = st_rate_start (sw->info.freq, hw_cap->info.freq);
-        if (!sw->rate) {
-            dolog ("Could not start rate conversion for `%s'\n", SW_NAME (sw));
-            g_free (sw);
-            return -1;
-        }
         QLIST_INSERT_HEAD (&hw_cap->sw_head, sw, entries);
         QLIST_INSERT_HEAD (&hw->cap_head, sc, entries);
 #ifdef DEBUG_CAPTURE
diff --git a/audio/audio_template.h b/audio/audio_template.h
index 33af42ed..dfa440f 100644
--- a/audio/audio_template.h
+++ b/audio/audio_template.h
@@ -141,11 +141,7 @@
 #else
     sw->rate = st_rate_start (sw->hw->info.freq, sw->info.freq);
 #endif
-    if (!sw->rate) {
-        g_free (sw->buf);
-        sw->buf = NULL;
-        return -1;
-    }
+
     return 0;
 }
 
diff --git a/audio/mixeng.c b/audio/mixeng.c
index 100a306..fe454e0 100644
--- a/audio/mixeng.c
+++ b/audio/mixeng.c
@@ -414,12 +414,7 @@
  */
 void *st_rate_start (int inrate, int outrate)
 {
-    struct rate *rate = audio_calloc(__func__, 1, sizeof(*rate));
-
-    if (!rate) {
-        dolog ("Could not allocate resampler (%zu bytes)\n", sizeof (*rate));
-        return NULL;
-    }
+    struct rate *rate = g_new0(struct rate, 1);
 
     rate->opos = 0;