configure: fix g729 decoder dependencies

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -2065,7 +2065,7 @@ flv_encoder_select="h263_encoder"
 fourxm_decoder_select="blockdsp bswapdsp"
 fraps_decoder_select="bswapdsp huffman"
 g2m_decoder_select="blockdsp dsputil zlib"
-g729_decoder_select="dsputil"
+g729_decoder_select="audiodsp"
 h261_decoder_select="mpeg_er mpegvideo"
 h261_encoder_select="aandcttables mpegvideoenc"
 h263_decoder_select="error_resilience h263_parser h263dsp mpeg_er mpegvideo qpeldsp"