ac3enc: do not clip coefficients after transforms

In either encoder, its impossible for the coefficients to go past 25 bits
right after the MDCT. Our MDCT is numerically stable.
For the floating point encoder, in case a NaN is contained, lrintf() will
raise a floating point exception during the conversion.

libavcodec/ac3enc_template.c

@@ -383,9 +383,6 @@ int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt,
 
     apply_mdct(s);
 
-    clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1],
-                      AC3_MAX_COEFS * s->num_blocks * s->channels);
-
     s->cpl_on = s->cpl_enabled;
     ff_ac3_compute_coupling_strategy(s);