audio_policy: Fix volumes for ICS blob compat

Allow usage of the default audio_policy source, even if the primary
audio HAL is an ICS binary blob

Change-Id: I959a925f458e14380c2e5443b1378c4018d9f084
Attempt to fix WiFi
Ported from CM9 - https://github.com/MTCM9/android_hardware_libhardware_legacy/commit/e27ed83a8c3a1ff758b3378acaa3f7de56551973
Haven't tested this yet, so might need fixing
Signed-off-by: Gannon Macdonald <gannon050197@gmail.com>

Change-Id: Iec46d99fa6c6869bcfa4e13e4e6eea225b5e4345