hal: Garbage output in logcat

AudioPolicyManagerCustom is outputting garbage
for the following log and potentially crashing it.
    AudioPolicyManagerCustom: offload disabled by av.streaming.offload.enable = ^[;¤¶
It should not use prop_value.

Change-Id: I5dc388d273c12a7c736faa50aeeab684f9600125
1 file changed