virtio-gpu: make processpipe respect choice of connection type

bug: 146066070

At least for virtio gpu pipe, for now. This is to make it so that
eventually, clients of gfx stream can pick the transport and it can do
the process pipe logic without dependency on drivers other than what's
advertised by HostConnection.

Change-Id: I702000e4c35ed90a69ef5742278deec47149aa27
9 files changed