Fix bug in Faust::Transform<FPP,Cpu>::updateNonZeros().

If the function were called several times in a row the value would have been as many times too bigger. Use rather the temporary variable (previously not used, just declared) to calculate the non-zeros count and then override the totalNonZeros attribute. This bug is minor because normally we don't have to call it several times if a Transform is immutable.

src/faust_linear_operator/CPU/faust_Transform.hpp

@@ -325,7 +325,8 @@ void Faust::Transform<FPP,Cpu>::updateNonZeros()
 {
 	int totalNonZeros_tmp=0;
 	for (int i=0;i<size();i++)
-		totalNonZeros+=data[i].getNonZeros();
+		totalNonZeros_tmp+=data[i].getNonZeros();
+	totalNonZeros = totalNonZeros_tmp;
 }