Revert "ac3enc: use MUL64() to multiply fixed-point coefficients"

Author says, this is unneeded.

This reverts commit 67fc32ac61.

libavcodec/ac3enc.c

@@ -328,10 +328,10 @@ static void compute_rematrixing_strategy(AC3EncodeContext *s)
                 CoefType rt = block->mdct_coef[1][i];
                 CoefType md = lt + rt;
                 CoefType sd = lt - rt;
-                sum[0] += MUL_COEF(lt, lt);
-                sum[1] += MUL_COEF(rt, rt);
-                sum[2] += MUL_COEF(md, md);
-                sum[3] += MUL_COEF(sd, sd);
+                sum[0] += lt * lt;
+                sum[1] += rt * rt;
+                sum[2] += md * md;
+                sum[3] += sd * sd;
             }
 
             /* compare sums to determine if rematrixing will be used for this band */

libavcodec/ac3enc_fixed.h

@@ -36,8 +36,6 @@ typedef int16_t SampleType;
 typedef int32_t CoefType;
 typedef int64_t CoefSumType;
 
-#define MUL_COEF(a,b) MUL64(a,b)
-
 
 /**
  * Compex number.

libavcodec/ac3enc_float.h

@@ -36,8 +36,6 @@ typedef float SampleType;
 typedef float CoefType;
 typedef float CoefSumType;
 
-#define MUL_COEF(a,b) ((a)*(b))
-
 
 typedef struct AC3MDCTContext {
     const float *window;    ///< MDCT window function