audio: Improve code readability

Change-Id: I5b1f24ab6098a037559603a92b4a1a38987488f5
(cherry picked from commit 4b29ec95d88d7cb99a7c55f0d3297a3b8c2149c4)
diff --git a/audio/audio_hw.c b/audio/audio_hw.c
index 7b6d642..cc9e622 100644
--- a/audio/audio_hw.c
+++ b/audio/audio_hw.c
@@ -2885,7 +2885,7 @@
             }
         }
 #endif
-        if (val != 0) {
+        if (val != SND_DEVICE_NONE) {
             bool bt_sco_active = false;
 
             if (out->devices & AUDIO_DEVICE_OUT_ALL_SCO) {