avfilter/af_amix: Free inpads' names generically

Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/af_amix.c

@@ -553,10 +553,8 @@ static av_cold int init(AVFilterContext *ctx)
         if (!pad.name)
             return AVERROR(ENOMEM);
 
-        if ((ret = ff_append_inpad(ctx, &pad)) < 0) {
+        if ((ret = ff_append_inpad_free_name(ctx, &pad)) < 0)
-            av_freep(&pad.name);
             return ret;
-        }
     }
 
     s->fdsp = avpriv_float_dsp_alloc(0);
@@ -589,9 +587,6 @@ static av_cold void uninit(AVFilterContext *ctx)
     av_freep(&s->scale_norm);
     av_freep(&s->weights);
     av_freep(&s->fdsp);
-
-    for (i = 0; i < ctx->nb_inputs; i++)
-        av_freep(&ctx->input_pads[i].name);
 }
 
 static int query_formats(AVFilterContext *ctx)