avformat/utils: Don't trigger errors for multiple id3 tags.

avformat/utils: Don't trigger errors for multiple id3 tags.

Such errors may make sense for specific formats, but general parsing
logic shouldn't be treating these as errors regardless of the error
recognition mode.

Fixes loading of the following wave when using -err_detect explode:
https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/webaudio/resources/4ch-440.wav

Signed-off-by: Dale Curtis <dalecurtis@chromium.org>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>