Fixed device affinity compatability issue on user id affinities

Device affinities compatability was failing the second time the device
affinity API was called. The audio mix flags were changed with the
MIX_ROUTE_FLAG_DISALLOWS_PREFERRED_DEVICE flag on the first API
call, subsequent calls would fail verification.

Bug: 266773756
Bug: 237733218
Test: atest audiopolicy_tests
Change-Id: I346bcf998567406e1fcf09b4d848755a2b98f615