msm8660 audio: fix BT in-call routing on non-HTC phones

  * Code was introduced in http://review.cyanogenmod.com/#/c/23094/
    that chose SND_DEVICE_BT_EC_OFF if noise reduction is disabled.
    But, non-HTC phones define SND_DEVICE_BT_EC_OFF as -1 so the
    default of handset is used as fallback.
  * Put this code within #ifdef HTC_AOUSTIC_AUDIO.

Change-Id: I9b93d372a10a112266d0fbdb4178151ce784eb69

msm8660/AudioHardware.cpp

@@ -2025,12 +2025,12 @@ status_t AudioHardware::doAudioRouteOrMute(uint32_t device)
     }
 #endif
 
+#ifdef HTC_ACOUSTIC_AUDIO
     if (device == SND_DEVICE_BT) {
         if (!mBluetoothNrec)
             device = SND_DEVICE_BT_EC_OFF;
     }
 
-#ifdef HTC_ACOUSTIC_AUDIO
     if (support_aic3254) {
         aic3254_config(device);
         do_aic3254_control(device);