Move audio config props to audio_config_prop

Bug: 155844385
Test: sepolicy_tests
Change-Id: Ic199925b5e3e1c80f1e692c8c5fc2cbb73eda0f5
diff --git a/private/audioserver.te b/private/audioserver.te
index 067152f..5047e2c 100644
--- a/private/audioserver.te
+++ b/private/audioserver.te
@@ -98,3 +98,6 @@
 
 # Allow using wake locks
 wakelock_use(audioserver)
+
+# Allow reading audio config props, e.g. af.fast_track_multiplier
+get_prop(audioserver, audio_config_prop)