ResourceImporterWAV: remove unnecessary var declaration

editor/import/resource_importer_wav.cpp

@@ -330,14 +330,12 @@ Error ResourceImporterWAV::import(const String &p_source_file, const String &p_s
 			for (int i = 0; i < new_data_frames; i++) {
 				// Cubic interpolation should be enough.
 
-				float mu = frac;
-
 				float y0 = data[MAX(0, ipos - 1) * format_channels + c];
 				float y1 = data[ipos * format_channels + c];
 				float y2 = data[MIN(frames - 1, ipos + 1) * format_channels + c];
 				float y3 = data[MIN(frames - 1, ipos + 2) * format_channels + c];
 
-				new_data.write[i * format_channels + c] = Math::cubic_interpolate(y1, y2, y0, y3, mu);
+				new_data.write[i * format_channels + c] = Math::cubic_interpolate(y1, y2, y0, y3, frac);
 
 				// update position and always keep fractional part within ]0...1]
 				// in order to avoid 32bit floating point precision errors