g723_1: fix off-by-one error in normalize_bits()

libavcodec/g723_1.c

@@ -274,7 +274,7 @@ static int normalize_bits(int num, int width)
     if (num < 0)
         num = ~num;
 
-    return width - av_log2(num);
+    return width - av_log2(num) - 1;
 }
 
 /**