libopencore-amr: fix memleak

Signed-off-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/libopencore-amr.c

@@ -202,6 +202,7 @@ static av_cold int amr_nb_encode_init(AVCodecContext *avctx)
     s->enc_state = Encoder_Interface_init(s->enc_dtx);
     if (!s->enc_state) {
         av_log(avctx, AV_LOG_ERROR, "Encoder_Interface_init error\n");
+        av_freep(&avctx->coded_frame);
         return -1;
     }