Fix "iirfilter.c:55: warning: unused variable ‘size’"

Originally committed as revision 19397 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/iirfilter.c

@@ -52,7 +52,7 @@ struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType filt_type
                                                     int order, float cutoff_ratio,
                                                     float stopband, float ripple)
 {
-    int i, j, size;
+    int i, j;
     FFIIRFilterCoeffs *c;
     double wa;
     double p[MAXORDER + 1][2];