The opus.c file uses ff_celt_freq_range and ff_celt_freq_bands which are
defined in opustab.c.  The opus parser needs to include that file to
avoid linker errors when not including the opus encoder/decoder.
Signed-off-by: Jacob Trimble <modmaker@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>