aac_ac3_parser: simplify an expression

Signed-off-by: Diego Biurrun <diego@biurrun.de>

libavcodec/aac_ac3_parser.c

@@ -82,13 +82,9 @@ get_next:
     if (avctx->codec_id != AV_CODEC_ID_AAC) {
         avctx->sample_rate = s->sample_rate;
 
-        /* allow downmixing to stereo (or mono for AC-3) */
-        if(avctx->request_channels > 0 &&
-                avctx->request_channels < s->channels &&
-                (avctx->request_channels <= 2 ||
-                (avctx->request_channels == 1 &&
-                (avctx->codec_id == AV_CODEC_ID_AC3 ||
-                 avctx->codec_id == AV_CODEC_ID_EAC3)))) {
+        /* (E-)AC-3: allow downmixing to stereo or mono */
+        if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
+            avctx->request_channels < s->channels) {
             avctx->channels = avctx->request_channels;
         } else {
             avctx->channels = s->channels;