camera: Only try to open actual webcam nodes

Going all the way down to video0 will make it try to use the display's
nodes, and hard-freeze in the process

Change-Id: Ia89f222a02947cbced78e2ee091282d11e334e8e
neflix WA: Search explicity for type 6 before deciding to bail out

Change-Id: I38990d69438f77c58e3e54b73dd9b80536e47c8e