Add delay to coefficient loader fix.

I thought the time taken to read back and then write zero back to the
DAP_FILTER_COEF_ACCESS WR bit would be enough but coefficients did not
load to the selected filter, tried 1ms delay instead still didn't work -
chances are that either not zero-ing or only zero-ing just before
writing the DAP_COEF_WR_xx_xSB registers would be fine but for now I'd
prefer to zero it sooner than later.

Audio.cpp

@@ -3193,7 +3193,7 @@ void AudioControlSGTL5000::load_peq(uint8_t filterNum, int *filterParameters)
 	write(DAP_COEF_WR_A2_MSB,(*filterParameters>>4)&65535);
 	write(DAP_COEF_WR_A2_LSB,(*filterParameters++)&15);
 	write(DAP_FILTER_COEF_ACCESS,(uint16_t)0x100|filterNum);
-	// This next step should be unnecessary but I'd prefer to do it for now
+	delay(10); // seems necessary, didn't work for 1ms.
 	modify(DAP_FILTER_COEF_ACCESS,(uint16_t)filterNum,15); 
 }