audio policy: fix audio device properties loading

Only load removable digital device properties from streams
with dynamic profiles. This avoids aggregating properties from
other stream profiles when the device can also be reached via those
profiles.

Bug: 38423100
Test: connect various USB devices and check properties are loaded
properly.

Change-Id: Ie5eed397d3a475848a3d423d18ffae9d55917ac4
5 files changed