Use symbol AUDIO_DEVICE_NONE from <system/audio.h>

Change-Id: I61f882c5e7c949bf00d3bfc745ebf3b5e1c42a58
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 50179c5..29b51fb 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1561,7 +1561,7 @@
     ALOGV("openOutput(), offloadInfo %p version 0x%04x",
           offloadInfo, offloadInfo == NULL ? -1 : offloadInfo->version);
 
-    if (pDevices == NULL || *pDevices == 0) {
+    if (pDevices == NULL || *pDevices == AUDIO_DEVICE_NONE) {
         return 0;
     }
 
@@ -1775,7 +1775,7 @@
     audio_format_t reqFormat = config.format;
     audio_channel_mask_t reqChannelMask = config.channel_mask;
 
-    if (pDevices == NULL || *pDevices == 0) {
+    if (pDevices == NULL || *pDevices == AUDIO_DEVICE_NONE) {
         return 0;
     }