V4L/DVB: gspca - gl860: USB control message delay unification

- 1 ms "msleep" applied to each sensor after USB control data exchange
  This was done for two sensors because these exchanges were known to
  be too quick depending on laptop model.
  It is fairly logical to apply this delay to each sensor
  in order to prevent from having errors with untested hardwares.

Signed-off-by: Olivier Lorin <o.lorin@laposte.net>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>