libfdk-aacdec: Reduce the default decoder delay by one frame

The default error concealment method if none is set via
aacDecoder_SetParam(AAC_CONCEAL_METHOD) is set in
CConcealment_InitCommonData within the fdk-aac library
and is set to Energy Interpolation. This method requires one frame
delay to the output. To reduce the default decoder output delay and
avoid missing the last frame in file based decoding, use Noise
Substitution as the default concealment method.

Signed-off-by: Omer Osman <omer.osman@iis.fraunhofer.de>
Signed-off-by: Martin Storsjö <martin@martin.st>