- call a new subdriver function 'isoc_init' before chosing the first
  alternate setting.
- call a new subdriver function 'isoc_nego' when submitting the URBs failed.
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>