audio/cmus: FFmpeg 6.0 compatibility fix

Patch required to build with FFmpeg 6.0

Reference:
https://git.alpinelinux.org/aports/tree/community/cmus/ffmpeg6.patch

PR:		270179

audio/cmus/files/patch-ip_ffmpeg.c

@@ -0,0 +1,12 @@
+--- ip/ffmpeg.c.orig	2022-07-05 20:20:28 UTC
++++ ip/ffmpeg.c
+@@ -202,9 +202,6 @@ static int ffmpeg_open(struct input_plugin_data *ip_da
+ 			break;
+ 		}
+ 
+-		if (codec->capabilities & AV_CODEC_CAP_TRUNCATED)
+-			cc->flags |= AV_CODEC_FLAG_TRUNCATED;
+-
+ 		if (avcodec_open2(cc, codec, NULL) < 0) {
+ 			d_print("could not open codec: %d, %s\n", cc->codec_id, avcodec_get_name(cc->codec_id));
+ 			err = -IP_ERROR_UNSUPPORTED_FILE_TYPE;