Some webcams with image transfer by bulk messages accept one or many
permanent bulk read.
Signed-off-by: NAntonio Ospite <ospite@studenti.unina.it>
Signed-off-by: NJean-Francois Moine <moinejf@free.fr>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>