mail/thunderbird: fix build on powerpc64
12537 /wrkdirs/usr/ports/mail/thunderbird/work/thunderbird-91.2.0/dom/media/flac/FlacDecoder.cpp:21:20: error: no matching member function for call to 'SupportsMimeType'
12538 platform->SupportsMimeType("audio/flac"_ns,
12539 ~~~~~~~~~~^~~~~~~~~~~~~~~~
12540 /wrkdirs/usr/ports/mail/thunderbird/work/.build/dist/include/PDMFactory.h:85:15: note: candidate function not viable: no known conversion from 'nullptr_t' to 'const mozilla::PDMFactory::MediaCodecsSupported' (aka 'const EnumSet<mozilla::PDMFactory::MediaCodecs>') for 2nd argument
12541 static bool SupportsMimeType(const nsACString& aMimeType,
12542 ^
12543 /wrkdirs/usr/ports/mail/thunderbird/work/.build/dist/include/PDMFactory.h:47:8: note: candidate function not viable: requires single argument 'aMimeType', but 2 arguments were provided
12544 bool SupportsMimeType(const nsACString& aMimeType) const;